Generic Name: CLARITHROMYCIN
Brand Name: Clarithromycin
- Substance Name(s):
- CLARITHROMYCIN
WARNINGS
Use In Pregnancy CLARITHROMYCIN SHOULD NOT BE USED IN PREGNANT WOMEN EXCEPT IN CLINICAL CIRCUMSTANCES WHERE NO ALTERNATIVE THERAPY IS APPROPRIATE. IF PREGNANCY OCCURS WHILE TAKING THIS DRUG, THE PATIENT SHOULD BE APPRISED OF THE POTENTIAL HAZARD TO THE FETUS. CLARITHROMYCIN HAS DEMONSTRATED ADVERSE EFFECTS OF PREGNANCY OUTCOME AND/OR EMBRYO-FETAL DEVELOPMENT IN MONKEYS, RATS, MICE, AND RABBITS AT DOSES THAT PRODUCED PLASMA LEVELS 2 TO 17 TIMES THE SERUM LEVELS ACHIEVED IN HUMANS TREATED AT THE MAXIMUM RECOMMENDED HUMAN DOSES. (See PRECAUTIONS: Pregnancy.) Hepatotoxicity Hepatic dysfunction, including increased liver enzymes, and hepatocellular and/or cholestatic hepatitis, with or without jaundice, has been reported with clarithromycin. This hepatic dysfunction may be severe and is usually reversible. In some instances, hepatic failure with fatal outcome has been reported and generally has been associated with serious underlying diseases and/or concomitant medications. Discontinue clarithromycin immediately if signs and symptoms of hepatitis occur. QT Prolongation Clarithromycin has been associated with prolongation of the QT interval and infrequent cases of arrhythmia. Cases of torsades de pointes have been spontaneously reported during postmarketing surveillance in patients receiving clarithromycin. Fatalities have been reported. Clarithromycin should be avoided in patients with ongoing proarrhythmic conditions such as uncorrected hypokalemia or hypomagnesemia, clinically significant bradycardia (see CONTRAINDICATIONS ) and in patients receiving Class IA (quinidine, procainamide) or Class III (dofetilide, amiodarone, sotalol) antiarrhythmic agents. Elderly patients may be more susceptible to drug-associated effects on the QT interval. Drug Interactions Serious adverse reactions have been reported in patients taking clarithromycin concomitantly with CYP3A4 substrates. These include colchicine toxicity with colchicine; rhabdomyolysis with simvastatin, lovastatin, and atorvastatin; and hypotension with calcium channel blockers metabolized by CYP3A4 (e.g., verapamil, amlodipine, diltiazem) (see PRECAUTIONS: Drug Interactions ). Life-threatening and fatal drug interactions have been reported in patients treated with clarithromycin and colchicine. Clarithromycin is a strong CYP3A4 inhibitor and this interaction may occur while using both drugs at their recommended doses. If co-administration of clarithromycin and colchicine is necessary in patients with normal renal and hepatic function, the dose of colchicine should be reduced. Patients should be monitored for clinical symptoms of colchicine toxicity. Concomitant administration of clarithromycin and colchicine is contraindicated in patients with renal or hepatic impairment (see CONTRAINDICATIONS and PRECAUTIONS: Drug Interactions ). Clostridium difficile Associated Diarrhea Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including clarithromycin, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile. C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibiotic use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents. If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C. difficile, and surgical evaluation should be instituted as clinically indicated. For information about warnings of other drugs indicated in combination with clarithromycin, refer to the section of their package inserts. Acute Hypersensitivity Reactions In the event of severe acute hypersensitivity reactions, such as anaphylaxis, Stevens-Johnson Syndrome, toxic epidermal necrolysis, drug rash with eosinophilia and systemic symptoms (DRESS), and Henoch-Schonlein purpura clarithromycin therapy should be discontinued immediately and appropriate treatment should be urgently initiated. Oral Hypoglycemic Agents/Insulin The concomitant use of clarithromycin and oral hypoglycemic agents and/or insulin can result in significant hypoglycemia. With certain hypoglycemic drugs such as nateglinide, pioglitazone, repaglinide and rosiglitazone, inhibition of CYP3A enzyme by clarithromycin may be involved and could cause hypolgycemia when used concomitantly. Careful monitoring of glucose is recommended. Oral Anticoagulants There is a risk of serious hemorrhage and significant elevations in INR and prothrombin time when clarithromycin is co-administered with warfarin. INR and prothrombin times should be frequently monitored while patients are receiving clarithromycin and oral anticoagulants concurrently. HMG-CoA Reductase Inhibitors (statins) Concomitant use of clarithromycin with lovastatin or simvastatin is contraindicated (see CONTRAINDICATIONS ) as these statins are extensively metabolized by CYP3A4, and concomitant treatment with clarithromycin increases their plasma concentration, which increases the risk of myopathy, including rhabdomyolysis. Cases of rhabdomyolysis have been reported in patients taking clarithromycin concomitantly with these statins. If treatment with clarithromycin cannot be avoided, therapy with lovastatin or simvastatin must be suspended during the course of treatment. Caution should be exercised when prescribing clarithromycin with statins. In situations where the concomitant use of clarithromycin with atorvastatin or pravastatin cannot be avoided, atorvastatin dose should not exceed 20 mg daily and pravastatin dose should not exceed 40 mg daily. Use of a statin that is not dependent on CYP3A metabolism (e.g.fluvastatin) can be considered. It is recommended to prescribe the lowest registered dose if concomitant use cannot be avoided.
DRUG INTERACTIONS
Drug Interactions Clarithromycin use in patients who are receiving theophylline may be associated with an increase of serum theophylline concentrations. Monitoring of serum theophylline concentrations should be considered for patients receiving high doses of theophylline or with baseline concentrations in the upper therapeutic range. In two studies in which theophylline was administered with clarithromycin (a theophylline sustained-release formulation was dosed at either 6.5 mg/kg or 12 mg/kg together with 250 or 500 mg q12h clarithromycin), the steady-state levels of C max, C min, and the area under the serum concentration time curve (AUC) of theophylline increased about 20%. Hypotension, bradyarrhythmias, and lactic acidosis have been observed in patients receiving concurrent verapamil, belonging to the calcium channel blockers drug class. Concomitant administration of single doses of clarithromycin and carbamazepine has been shown to result in increased plasma concentrations of carbamazepine. Blood level monitoring of carbamazepine may be considered. When clarithromycin and terfenadine were coadministered, plasma concentrations of the active acid metabolite of terfenadine were threefold higher, on average, than the values observed when terfenadine was administered alone. The pharmacokinetics of clarithromycin and the 14-hydroxy-clarithromycin were not significantly affected by coadministration of terfenadine once clarithromycin reached steady-state conditions. Concomitant administration of clarithromycin with terfenadine is contraindicated. (See CONTRAINDICATIONS .) Clarithromycin 500 mg every 8 hours was given in combination with omeprazole 40 mg daily to healthy adult subjects. The steady-state plasma concentrations of omeprazole were increased (C max, AUC 0-24, and T 1/2 increases of 30%, 89%, and 34%, respectively), by the concomitant administration of clarithromycin. The mean 24-hour gastric pH value was 5.2 when omeprazole was administered alone and 5.7 when co-administered with clarithromycin. Co-administration of clarithromycin with ranitidine bismuth citrate resulted in increased plasma ranitidine concentrations (57%), increased plasma bismuth trough concentrations (48%), and increased 14-hydroxy-clarithromycin plasma concentrations (31%). These effects are clinically insignificant. Simultaneous oral administration of clarithromycin tablets and zidovudine to HIV-infected adult patients may result in decreased steady-state zidovudine concentrations. Following administration of clarithromycin 500 mg tablets twice daily with zidovudine 100 mg every 4 hours, the steady-state zidovudine AUC decreased 12% compared to administration of zidovudine alone (n=4). Individual values ranged from a decrease of 34% to an increase of 14%. When clarithromycin tablets were administered two to four hours prior to zidovudine, the steady-state zidovudine C max increased 100% whereas the AUC was unaffected (n=24). Administration of clarithromycin and zidovudine should be separated by at least two hours. The impact of co-administration of clarithromycin extended-release tablets and zidovudine has not been evaluated. Simultaneous administration of clarithromycin tablets and didanosine to 12 HIV-infected adult patients resulted in no statistically significant change in didanosine pharmacokinetics. Following administration of fluconazole 200 mg daily and clarithromycin 500 mg twice daily to 21 healthy volunteers, the steady-state clarithromycin C min and AUC increased 33% and 18%, respectively. Steady-state concentrations of 14-OH clarithromycin were not significantly affected by concomitant administration of fluconazole. No dosage adjustment of clarithromycin is necessary when co-administered with fluconazole. Ritonavir Concomitant administration of clarithromycin and ritonavir (n=22) resulted in a 77% increase in clarithromycin AUC and a 100% decrease in the AUC of 14-OH clarithromycin. Clarithromycin may be administered without dosage adjustment to patients with normal renal function taking ritonavir. Since concentrations of 14-OH clarithromycin are significantly reduced when clarithromycin is co-administered with ritonavir, alternative antibacterial therapy should be considered for indications other than infections due to Mycobacterium avium complex (see PRECAUTIONS: Drug Interactions ). Doses of clarithromycin greater than 1000 mg per day should not be co-administered with protease inhibitors. Spontaneous reports in the post-marketing period suggest that concomitant administration of clarithromycin and oral anticoagulants may potentiate the effects of the oral anticoagulants. Prothrombin times should be carefully monitored while patients are receiving clarithromycin and oral anticoagulants simultaneously. Digoxin is a substrate for P-glycoprotein (Pgp) and clarithromycin is known to inhibit Pgp. When clarithromycin and digoxin are co-administered, inhibition of Pgp by clarithromycin may lead to increased exposure of digoxin. Elevated digoxin serum concentrations in patients receiving clarithromycin and digoxin concomitantly have been reported in post-marketing surveillance. Some patients have shown clinical signs consistent with digoxin toxicity, including potentially fatal arrhythmias. Monitoring of serum digoxin concentrations should be considered, especially for patients with digoxin concentrations in the upper therapeutic range. Co-administration of clarithromycin, known to inhibit CYP3A, and a drug primarily metabolized by CYP3A may be associated with elevations in drug concentrations that could increase or prolong both therapeutic and adverse effects of the concomitant drug. Clarithromycin should be used with caution in patients receiving treatment with other drugs known to be CYP3A enzyme substrates, especially if the CYP3A substrate has a narrow safety margin (e.g., carbamazepine) and/or the substrate is extensively metabolized by this enzyme. Dosage adjustments may be considered, and when possible, serum concentrations of drugs primarily metabolized by CYP3A should be monitored closely in patients concurrently receiving clarithromycin. The following are examples of some clinically significant CYP3A based drug interactions. Interactions with other drugs metabolized by the CYP3A isoform are also possible. Carbamazepine and Terfenadine Increased serum concentrations of carbamazepine and the active acid metabolite of terfenadine were observed in clinical trials with clarithromycin. Colchicine Colchicine is a substrate for both CYP3A and the efflux transporter, P-glycoprotein (Pgp). Clarithromycin and other macrolides are known to inhibit CYP3A and Pgp. When a single dose of colchicine 0.6 mg was administered with clarithromycin 250 mg BID for 7 days, the colchicine C max increased 197% and the AUC0-∞ increased 239% compared to administration of colchicine alone. The dose of colchicine should be reduced when co-administered with clarithromycin in patients with normal renal and hepatic function. Concomitant use of clarithromycin and colchicine is contraindicated in patients with renal or hepatic impairment. (See WARNINGS ). Efavirenz, Nevirapine, Rifampicin, Rifabutin, and Rifapentine Inducers of CYP3A enzymes, such as efavirenz, nevirapine, rifampicin, rifabutin, and rifapentine will increase the metabolism of clarithromycin, thus decreasing plasma concentrations of clarithromycin, while increasing those of 14-OH-clarithromycin. Since the microbiological activities of clarithromycin and 14-OHclarithromycin are different for different bacteria, the intended therapeutic effect could be impaired during concomitant administration of clarithromycin and enzyme inducers. Alternative antibacterial treatment should be considered when treating patients receiving inducers of CYP3A. Sildenafil, Tadalafil, and Vardenafil Each of these phosphodiesterase inhibitors is primarily metabolized by CYP3A, and CYP3A will be inhibited by concomitant administration of clarithromycin. Co-administration of clarithromycin with sildenafil, tadalafil, or vardenafil will result in increased exposure of these phosphodiesterase inhibitors. Coadministration of these phosphodiesterase inhibitors with clarithromycin is not recommended. Tolterodine The primary route of metabolism for tolterodine is via CYP2D6. However, in a subset of the population devoid of CYP2D6, the identified pathway of metabolism is via CYP3A. In this population subset, inhibition of CYP3A results in significantly higher serum concentrations of tolterodine. Tolterodine 1 mg twice daily is recommended in patients deficient in CYP2D6 activity (poor metabolizers) when co-administered with clarithromycin. Triazolobenzodiazepines (e.g., alprazolam, midazolam, triazolam) When a single dose of midazolam was co-administered with clarithromycin tablets (500 mg twice daily for 7 days), midazolam AUC increased 174% after intravenous administration of midazolam and 600% after oral administration. When oral midazolam is co-administered with clarithromycin, dose adjustments may be necessary and possible prolongation and intensity of effect should be anticipated. Caution and appropriate dose adjustments should be considered when triazolam or alprazolam is co-administered with clarithromycin. For benzodiazepines which are not metabolized by CYP3A (e.g., temazepam, nitrazepam, lorazepam), a clinically important interaction with clarithromycin is unlikely. There have been post-marketing reports of drug interactions and central nervous system (CNS) effects (e.g., somnolence and confusion) with the concomitant use of clarithromycin and triazolam. Monitoring the patient for increased CNS pharmacological effects is suggested. Atazanavir Both clarithromycin and atazanavir are substrates and inhibitors of CYP3A, and there is evidence of a bidirectional drug interaction. Following administration of clarithromycin (500 mg twice daily) with atazanavir (400 mg once daily), the clarithromycin AUC increased 94%, the 14-OH clarithromycin AUC decreased 70% and the atazanavir AUC increased 28%. When clarithromycin is co-administered with atazanavir, the dose of clarithromycin should be decreased by 50%. Since concentrations of 14-OH clarithromycin are significantly reduced when clarithromycin is co-administered with atazanavir, alternative antibacterial therapy should be considered for indications other than infections due to Mycobacterium avium complex (see PRECAUTIONS: Drug Interactions ). Doses of clarithromycin greater than 1000 mg per day should not be co-administered with protease inhibitors. Itraconazole Both clarithromycin and itraconazole are substrates and inhibitors of CYP3A, potentially leading to a bidirectional drug interaction when administered concomitantly. Clarithromycin may increase the plasma concentrations of itraconazole, while itraconazole may increase the plasma concentrations of clarithromycin. Patients taking itraconazole and clarithromycin concomitantly should be monitored closely for signs or symptoms of increased or prolonged adverse reactions. Saquinavir Both clarithromycin and saquinavir are substrates and inhibitors of CYP3A and there is evidence of a bidirectional drug interaction. Following administration of clarithromycin (500 mg bid) and saquinavir (soft gelatin capsules, 1200 mg tid) to 12 healthy volunteers, the steady-state saquinavir AUC and C max increased 177% and 187% respectively compared to administration of saquinavir alone. Clarithromycin AUC and C max increased 45% and 39% respectively, whereas the 14–OH clarithromycin AUC and C max decreased 24% and 34% respectively, compared to administration with clarithromycin alone. No dose adjustment of clarithromycin is necessary when clarithromycin is co-administered with saquinavir in patients with normal renal function. When saquinavir is co-administered with ritonavir, consideration should be given to the potential effects of ritonavir on clarithromycin (refer to interaction between clarithromycin and ritonavir) (see PRECAUTIONS: Drug Interactions ). The following CYP3A based drug interactions have been observed with erythromycin products and/or with clarithromycin in post-marketing experience: Antiarrhythmics There have been postmarketing reports of torsades de pointes occurring with concurrent use of clarithromycin and quinidine or disopyramide. Electrocardiograms should be monitored for QTc prolongation during coadministration of clarithromycin with these drugs. Serum concentrations of these medications should also be monitored. Ergotamine/Dihydroergotamine Post-marketing reports indicate that coadministration of clarithromycin with ergotamine or dihydroergotamine has been associated with acute ergot toxicity characterized by vasospasm and ischemia of the extremities and other tissues including the central nervous system. Concomitant administration of clarithromycin with ergotamine or dihydroergotamine is contraindicated (see CONTRAINDICATIONS ). Triazolobenzodiazepines (such as Triazolam and Alprazolam) and Related Benzodiazepines (such as Midazolam) Erythromycin has been reported to decrease the clearance of triazolam and midazolam, and thus, may increase the pharmacologic effect of these benzodiazepines. There have been post-marketing reports of drug interactions and CNS effects (e.g., somnolence and confusion) with the concomitant use of clarithromycin and triazolam. Sildenafil (Viagra) Erythromycin has been reported to increase the systemic exposure (AUC) of sildenafil. A similar interaction may occur with clarithromycin; reduction of sildenafil dosage should be considered. (See Viagra package insert.) There have been spontaneous or published reports of CYP3A based interactions of erythromycin and/or clarithromycin with cyclosporine, carbamazepine, tacrolimus, alfentanil, disopyramide, rifabutin, quinidine, methylprednisolone, cilostazol, bromocriptine and vinblastine. Concomitant administration of clarithromycin with cisapride, pimozide, astemizole, or terfenadine is contraindicated (see CONTRAINDICATIONS ). In addition, there have been reports of interactions of erythromycin or clarithromycin with drugs not thought to be metabolized by CYP3A, including hexobarbital, phenytoin, and valproate.
OVERDOSAGE
Overdosage of clarithromycin can cause gastrointestinal symptoms such as abdominal pain, vomiting, nausea, and diarrhea. Adverse reactions accompanying overdosage should be treated by the prompt elimination of unabsorbed drug and supportive measures. As with other macrolides, clarithromycin serum concentrations are not expected to be appreciably affected by hemodialysis or peritoneal dialysis.
DESCRIPTION
Clarithromycin is a semi-synthetic macrolide antibiotic. Chemically, it is 6-0-methylerythromycin. The molecular formula is C 38H 69NO 13, and the molecular weight is 747.96. The structural formula is: Clarithromycin is a white to off-white crystalline powder. It is soluble in acetone, slightly soluble in methanol, ethanol, and acetonitrile, and practically insoluble in water. Each clarithromycin tablet intended for oral administration contains 250 mg or 500 mg of clarithromycin. In addition, each clarithromycin tablet contains the following inactive ingredients: croscarmellose sodium, hypromellose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polysorbate 80, povidone, talc, and titanium dioxide. Clarithromycin chemical structure
CLINICAL STUDIES
Mycobacterial Infections Prophylaxis A randomized, double-blind study (561) compared clarithromycin 500 mg b.i.d. to placebo in patients with CDC-defined AIDS and CD 4 counts <100 cells/µL. This study accrued 682 patients from November 1992 to January 1994, with a median CD 4 cell count at study entry of 30 cells/µL. Median duration of clarithromycin was 10.6 months vs. 8.2 months for placebo. More patients in the placebo arm than the clarithromycin arm discontinued prematurely from the study (75.6% and 67.4%, respectively). However, if premature discontinuations due to MAC or death are excluded, approximately equal percentages of patients on each arm (54.8% on clarithromycin and 52.5% on placebo) discontinued study drug early for other reasons. The study was designed to evaluate the following endpoints: MAC bacteremia, defined as at least one positive culture for M. aviumcomplex bacteria from blood or another normally sterile site. Survival Clinically significant disseminated MAC disease, defined as MAC bacteremia accompanied by signs or symptoms of serious MAC infection, including fever, night sweats, weight loss, anemia, or elevations in liver function tests. MAC Bacteremia In patients randomized to clarithromycin, the risk of MAC bacteremia was reduced by 69% compared to placebo. The difference between groups was statistically significant (p2% Adverse Event Incidence Rates for either treatment group. Adverse Event Clarithromycin (n = 339) % Placebo (n = 339) % Body as a Whole Abdominal Pain 5.0% 3.5% Headache 2.7% 0.9% Digestive Diarrhea 7.7% 4.1% Dyspepsia 3.8% 2.7% Flatulence 2.4% 0.9% Nausea 11.2% 7.1% Vomiting 5.9% 3.2% Skin & Appendages Rash 3.2% 3.5% Special Senses Taste Perversion 8.0% 0.3% Among these events, taste perversion was the only event that had significantly higher incidence in the clarithromycin-treated group compared to the placebo-treated group. Discontinuation due to adverse events was required in 18% of patients receiving clarithromycin compared to 17% of patients receiving placebo in this trial. Primary reasons for discontinuation in clarithromycin treated patients include headache, nausea, vomiting, depression and taste perversion. Changes in Laboratory Values of Potential Clinical Importance In immuno-compromised patients receiving prophylaxis against M. avium, evaluations of laboratory values were made by analyzing those values outside the seriously abnormal value (i.e., the extreme high or low limit) for the specified test. Percentage of Patients Includes only patients with baseline values within the normal range or borderline high (hematology variables) and within the normal range or borderline low (chemistry variables). Exceeding Extreme Laboratory Value in Patients Receiving Prophylaxis Against M. avium Complex Clarithromycin 500 mg b.i.d. Placebo Hemoglobin <8 g/dL 4/118 3% 5/103 5% Platelet Count <50 x 10 9/L 11/249 4% 12/250 5% WBC Count 5 x ULN ULN = Upper Limit of Normal 7/196 4% 5/208 2% SGPT >5 x ULN 6/217 3% 4/232 2% Alk. Phos. >5 x ULN 5/220 2% 5/218 2% Treatment Three randomized studies (500, 577, and 521) compared different dosages of clarithromycin in patients with CDC-defined AIDS and CD 4 counts <100 cells/mcL. These studies accrued patients from May 1991 to March 1992. Study 500 was randomized, double-blind; Study 577 was open-label compassionate use. Both studies used 500 and 1000 mg b.i.d. doses; Study 500 also had a 2000 mg b.i.d. group. Study 521 was a pediatric study at 3.75, 7.5, and 15 mg/kg b.i.d. Study 500 enrolled 154 adult patients, Study 577 enrolled 469 adult patients, and Study 521 enrolled 25 patients between the ages of 1 to 20. The majority of patients had CD 4 cell counts <50/mcL at study entry. The studies were designed to evaluate the following end points: Change in MAC bacteremia or blood cultures negative for M. avium. Change in clinical signs and symptoms of MAC infection including one or more of the following: fever, night sweats, weight loss, diarrhea, splenomegaly, and hepatomegaly. The results for the 500 study are described below. The 577 study results were similar to the results of the 500 study. Results with the 7.5 mg/kg b.i.d. dose in the pediatric study were comparable to those for the 500 mg b.i.d. regimen in the adult studies. Study 069 compared the safety and efficacy of clarithromycin in combination with ethambutol versus clarithromycin in combination with ethambutol and clofazimine for the treatment of disseminated MAC (dMAC) infection 5. This 24-week study enrolled 106 patients with AIDS and dMAC, with 55 patients randomized to receive clarithromycin and ethambutol, and 51 patients randomized to receive clarithromycin, ethambutol, and clofazimine. Baseline characteristics between study arms were similar with the exception of median CFU counts being at least 1 log higher in the clarithromycin, ethambutol, and clofazimine arm. Compared to prior experience with clarithromycin monotherapy, the two-drug regimen of clarithromycin and ethambutol was well tolerated and extended the time to microbiologic relapse, largely through suppressing the emergence of clarithromycin resistant strains. However, the addition of clofazimine to the regimen added no additional microbiologic or clinical benefit. Tolerability of both multidrug regimens was comparable with the most common adverse events being gastrointestinal in nature. Patients receiving the clofazimine-containing regimen had reduced survival rates; however, their baseline mycobacterial colony counts were higher. The results of this trial support the addition of ethambutol to clarithromycin for the treatment of initial dMAC infections but do not support adding clofazimine as a third agent. MAC Bacteremia Decreases in MAC bacteremia or negative blood cultures were seen in the majority of patients in all dose groups. Mean reductions in colony forming units (CFU) are shown below. Included in the table are results from a separate study with a four drug regimen 6 (ciprofloxacin, ethambutol, rifampicin, and clofazimine). Since patient populations and study procedures may vary between these two studies, comparisons between the clarithromycin results and the combination therapy results should be interpreted cautiously. Mean Reductions in Log CFU from Baseline (After 4 Weeks of Therapy) 500 mg b.i.d. (N=35) 1000 mg b.i.d. (N=32) 2000 mg b.i.d. (N=26) Four Drug Regimen (N=24) 1.5 2.3 2.3 1.4 Although the 1000 mg and 2000 mg b.i.d. doses showed significantly better control of bacteremia during the first four weeks of therapy, no significant differences were seen beyond that point. The percent of patients whose blood was sterilized as shown by one or more negative cultures at any time during acute therapy was 61% (30/49) for the 500 mg b.i.d. group and 59% (29/49) and 52% (25/48) for the 1000 and 2000 mg b.i.d. groups, respectively. The percent of patients who had 2 or more negative cultures during acute therapy that were sustained through study Day 84 was 25% (12/49) in both the 500 and 1000 mg b.i.d. groups and 8% (4/48) for the 2000 mg b.i.d. group. By Day 84, 23% (11/49), 37% (18/49), and 56% (27/48) of patients had died or discontinued from the study, and 14% (7/49), 12% (6/49), and 13% (6/48) of patients had relapsed in the 500, 1000, and 2000 mg b.i.d. dose groups, respectively. All of the isolates had an MIC 3% Hemoglobin Increase > 1 gm b.i.d. dose (mg) % ever gaining % gaining ≥ 6 weeks b.i.d. dose (mg) % ever increasing % increasing ≥ 6 weeks 500 33% 14% 500 58% 26% 1000 26% 17% 1000 37% 6% 2000 26% 12% 2000 62% 18% The median duration of response, defined as improvement or resolution of clinical signs and symptoms, was 2 to 6 weeks. Since the study was not designed to determine the benefit of monotherapy beyond 12 weeks, the duration of response may be underestimated for the 25 to 33% of patients who continued to show clinical response after 12 weeks. Survival Median survival time from study entry (Study 500) was 249 days at the 500 mg b.i.d. dose compared to 215 days with the 1000 mg b.i.d. dose. However, during the first 12 weeks of therapy, there were 2 deaths in 53 patients in the 500 mg b.i.d. group versus 13 deaths in 51 patients in the 1000 mg b.i.d. group. The reason for this apparent mortality difference is not known. Survival in the two groups was similar beyond 12 weeks. The median survival times for these dosages were similar to recent historical controls with MAC when treated with combination therapies. 5 Median survival time from study entry in Study 577 was 199 days for the 500 mg b.i.d. dose and 179 days for the 1000 mg b.i.d. dose. During the first four weeks of therapy, while patients were maintained on their originally assigned dose, there were 11 deaths in 255 patients taking 500 mg b.i.d. and 18 deaths in 214 patients taking 1000 mg b.i.d. Safety The adverse event profiles showed that both the 500 and 1000 mg b.i.d. doses were well tolerated. The 2000 mg b.i.d. dose was poorly tolerated and resulted in a higher proportion of premature discontinuations. In AIDS patients and other immunocompromised patients treated with the higher doses of clarithromycin over long periods of time for mycobacterial infections, it was often difficult to distinguish adverse events possibly associated with clarithromycin administration from underlying signs of HIV disease or intercurrent illness. The following analyses summarize experience during the first 12 weeks of therapy with clarithromycin. Data are reported separately for Study 500 (randomized, double-blind) and Study 577 (open-label, compassionate use) and also combined. Adverse events were reported less frequently in Study 577, which may be due in part to differences in monitoring between the two studies. In adult patients receiving clarithromycin 500 mg b.i.d., the most frequently reported adverse events, considered possibly or probably related to study drug, with an incidence of 5% or greater, are listed below. Most of these events were mild to moderate in severity, although 5% (Study 500: 8%; Study 577: 4%) of patients receiving 500 mg b.i.d. and 5% (Study 500: 4%; Study 577: 6%) of patients receiving 1000 mg b.i.d. reported severe adverse events. Excluding those patients who discontinued therapy or died due to complications of their underlying non-mycobacterial disease, approximately 8% (Study 500: 15%; Study 577: 7%) of the patients who received 500 mg b.i.d. and 12% (Study 500: 14%; Study 577: 12%) of the patients who received 1000 mg b.i.d. discontinued therapy due to drug-related events during the first 12 weeks of therapy. Overall, the 500 and 1000 mg b.i.d. doses had similar adverse event profiles. Treatment-related Includes those events possibly or probably related to study drug and excludes concurrent conditions. Adverse Event Incidence Rates (%) in Immunocompromised Adult Patients During the First 12 Weeks of Therapy with 500 mg b.i.d. Clarithromycin Dose Adverse Event Study 500 (n=53) Study 577 (n=255) Combined (n=308) Abdominal Pain 7.5 2.4 3.2 Diarrhea 9.4 1.6 2.9 Flatulence 7.5 0.0 1.3 Headache 7.5 0.4 1.6 Nausea 28.3 9.0 12.3 Rash 9.4 2.0 3.2 Taste Perversion 18.9 0.4 3.6 Vomiting 24.5 3.9 7.5 A limited number of pediatric AIDS patients have been treated with clarithromycin suspension for mycobacterial infections. The most frequently reported adverse events, excluding those due to the patient’s concurrent condition, were consistent with those observed in adult patients. Changes in Laboratory Values In immunocompromised patients treated with clarithromycin for mycobacterial infections, evaluations of laboratory values were made by analyzing those values outside the seriously abnormal level (i.e., the extreme high or low limit) for the specified test. Percentage of Patients Includes only patients with baseline values within the normal range or borderline high (hematology variables) and within the normal range or borderline low (chemistry variables) Exceeding Extreme Laboratory Value Limits During First 12 Weeks of Treatment 500 mg b.i.d. Dose Includes all values within the first 12 weeks for patients who start on 500 mg b.i.d. Study 500 Study 577 Combined BUN >50 mg/dL 0% <1% <1% Platelet Count <50 x 10 9/L 0% <1% 5 x ULN ULN = Upper Limit of Normal 0% 3% 2% SGPT >5 x ULN 0% 2% 1% WBC <1 x 10 9/L 0% 1% 1% Otitis Media In a controlled clinical study of acute otitis media performed in the United States, where significant rates of beta-lactamase producing organisms were found, clarithromycin was compared to an oral cephalosporin. In this study, very strict evaluability criteria were used to determine clinical response. For the 223 patients who were evaluated for clinical efficacy, the clinical success rate (i.e., cure plus improvement) at the post-therapy visit was 88% for clarithromycin and 91% for the cephalosporin. In a smaller number of patients, microbiologic determinations were made at the pre-treatment visit. The following presumptive bacterial eradication/clinical cure outcomes (i.e., clinical success) were obtained: U.S. Acute Otitis Media Study Clarithromycin vs. Oral Cephalosporin Efficacy Results Pathogen Outcome S. pneumoniae clarithromycin success rate, 13/15 (87%), control 4/5 H. influenzae None of the H. influenzae isolated pre-treatment was resistant to clarithromycin; 6% were resistant to the control agent. clarithromycin success rate, 10/14 (71%), control ¾ M. catarrhalis clarithromycin success rate, 4/5, control 1/1 S. pyogenes clarithromycin success rate, 3/3, control 0/1 Overall clarithromycin success rate, 30/37 (81%), control 8/11 (73%) Safety The incidence of adverse events in all patients treated, primarily diarrhea and vomiting, did not differ clinically or statistically for the two agents. In two other controlled clinical trials of acute otitis media performed in the United States, where significant rates of beta-lactamase producing organisms were found, clarithromycin was compared to an oral antimicrobial agent that contained a specific beta-lactamase inhibitor. In these studies, very strict evaluability criteria were used to determine the clinical responses. In the 233 patients who were evaluated for clinical efficacy, the combined clinical success rate (i.e., cure and improvement) at the post-therapy visit was 91% for both clarithromycin and the control. For the patients who had microbiologic determinations at the pre-treatment visit, the following presumptive bacterial eradication/clinical cure outcomes (i.e., clinical success) were obtained: Two U.S. Acute Otitis Media Studies Clarithromycin vs. Antimicrobial/Beta-lactamase Inhibitor Efficacy Results Pathogen Outcome S. pneumoniae clarithromycin success rate, 43/51 (84%), control 55/56 (98%) H. influenzae Of the H. influenzae isolated pre-treatment, 3% were resistant to clarithromycin and 10% were resistant to the control agent. clarithromycin success rate, 36/45 (80%), control 31/33 (94%) M. catarrhalis clarithromycin success rate, 9/10 (90%), control 6/6 S. pyogenes clarithromycin success rate, 3/3, control 5/5 Overall clarithromycin success rate, 91/109 (83%), control 97/100 (97%) Safety The incidence of adverse events in all patients treated, primarily diarrhea (15% vs. 38%) and diaper rash (3% vs. 11%) in young children, was clinically and statistically lower in the clarithromycin arm versus the control arm. Duodenal Ulcer Associated with H. pylori Infection Clarithromycin + Lansoprazole and Amoxicillin H. pylori Eradication for Reducing the Risk of Duodenal Ulcer Recurrence Two U.S. randomized, double-blind clinical studies in patients with H. pylori and duodenal ulcer disease (defined as an active ulcer or history of an active ulcer within one year) evaluated the efficacy of clarithromycin in combination with lansoprazole and amoxicillin capsules as triple 14-day therapy for eradication of H. pylori. Based on the results of these studies, the safety and efficacy of the following eradication regimen were established: Triple therapy: Clarithromycin 500 mg b.i.d. + Lansoprazole 30 mg b.i.d. + Amoxicillin 1 gm b.i.d. Treatment was for 14 days. H. pylori eradication was defined as two negative tests (culture and histology) at 4 to 6 weeks following the end of treatment. The combination of clarithromycin plus lansoprazole and amoxicillin as triple therapy was effective in eradicating H. pylori. Eradication of H. pylori has been shown to reduce the risk of duodenal ulcer recurrence. A randomized, double-blind clinical study performed in the U.S. in patients with H. pylori and duodenal ulcer disease (defined as an active ulcer or history of an ulcer within one year) compared the efficacy of clarithromycin in combination with lansoprazole and amoxicillin as triple therapy for 10 and 14 days. This study established that the 10-day triple therapy was equivalent to the 14-day triple therapy in eradicating H. pylori. H. pylori Eradication Rates-Triple Therapy (Clarithromycin/Lansoprazole/Amoxicillin) Percent of Patients Cured [95% Confidence Interval] (number of patients) Study Duration Triple Therapy Evaluable Analysis Based on evaluable patients with confirmed duodenal ulcer (active or within one year) and H. pylori infection at baseline defined as at least two of three positive endoscopic tests from CLOtest® (Delta West LTD., Bentley, Australia), histology, and/or culture. Patients were included in the analysis if they completed the study. Additionally, if patients were dropped out of the study due to an adverse event related to the study drug, they were included in the analysis as evaluable failures of therapy. Triple Therapy Intent-to-Treat Analysis Patients were included in the analysis if they had documented H. pylori infection at baseline as defined above and had a confirmed duodenal ulcer (active or within one year). All dropouts were included as failures of therapy. M93-131 14 days 92 (p<0.05) versus clarithromycin/lansoprazole and lansoprazole/amoxicillin dual therapy. [80.0 – 97.7] (n = 48) 86 c [73.3 – 93.5] (n = 55) M95-392 14 days 86 (p<0.05) versus clarithromycin/amoxicillin dual therapy. [75.7 – 93.6] (n = 66) 83 [72.0 – 90.8] (n = 70) M95-399 The 95% confidence interval for the difference in eradication rates, 10-day minus 14-day, is (-10.5, 8.1) in the evaluable analysis and (-9.7, 9.1) in the intent-to-treat analysis. 14 days 85 [77.0 – 91] (n = 113) 82 [73.9 – 88.1] (n = 126) 10 days 84 [76.0 – 89.8] (n = 123) 81 [73.9 – 87.6] (n = 135) Clarithromycin + Omeprazole and Amoxicillin Therapy H. pylori Eradication for Reducing the Risk of Duodenal Ulcer Recurrence Three U.S., randomized, double-blind clinical studies in patients with H. pylori infection and duodenal ulcer disease (n = 558) compared clarithromycin plus omeprazole and amoxicillin to clarithromycin plus amoxicillin. Two studies (Studies 126 and 127) were conducted in patients with an active duodenal ulcer, and the third study (Study 446) was conducted in patients with a duodenal ulcer in the past 5 years, but without an ulcer present at the time of enrollment. The dosage regimen in the studies was clarithromycin 500 mg b.i.d. plus omeprazole 20 mg b.i.d. plus amoxicillin 1 gram b.i.d. for 10 days. In Studies 126 and 127, patients who took the omeprazole regimen also received an additional 18 days of omeprazole 20 mg q.d. Endpoints studied were eradication of H. pylori and duodenal ulcer healing (studies 126 and 127 only). H. pylori status was determined by CLOtest®, histology, and culture in all three studies. For a given patient, H. pylori was considered eradicated if at least two of these tests were negative, and none was positive. The combination of clarithromycin plus omeprazole and amoxicillin was effective in eradicating H. pylori. Per-Protocol and Intent-To-Treat H. pylori Eradication Rates % of Patients Cured [95% Confidence Interval] Clarithromycin + Omeprazole + Amoxicillin Clarithromycin + Amoxicillin Per- Protocol Patients were included in the analysis if they had confirmed duodenal ulcer disease (active ulcer studies 126 and 127; history of ulcer within 5 years, study M96-446) and H. pylori infection at baseline defined as at least two of three positive endoscopic tests from CLOtest®, histology, and/or culture. Patients were included in the analysis if they completed the study. Additionally, if patients dropped out of the study due to an adverse event related to the study drug, they were included in the analysis as failures of therapy. The impact of eradication on ulcer recurrence has not been assessed in patients with a past history of ulcer. Intent- To-Treat Patients were included in the analysis if they had documented H. pylori infection at baseline and had confirmed duodenal ulcer disease. All dropouts were included as failures of therapy. Per- Protocol Intent- To-Treat Study 126 p<0.05 versus clarithromycin plus amoxicillin.77 [64, 86] (n = 64) 69 [57, 79] (n = 80) 43 [31, 56] (n = 67) 37 [27, 48] (n = 84) Study 127 78 [67, 88] (n = 65) 73 [61, 82] (n = 77) 41 [29, 54] (n = 68) 36 [26, 47] (n = 84) Study M96-446 90 [80, 96] (n = 69) 83 [74, 91] (n = 84) 33 [24, 44] (n = 93) 32 [23, 42] (n = 99) Safety In clinical trials using combination therapy with clarithromycin plus omeprazole and amoxicillin, no adverse reactions peculiar to the combination of these drugs have been observed. Adverse reactions that have occurred have been limited to those that have been previously reported with clarithromycin, omeprazole, or amoxicillin. The most frequent adverse experiences observed in clinical trials using combination therapy with clarithromycin plus omeprazole and amoxicillin (n=274) were diarrhea (14%), taste perversion (10%), and headache (7%). For information about adverse reactions with omeprazole or amoxicillin, refer to the ADVERSE REACTIONS section of their package inserts. Clarithromycin + Omeprazole Therapy Four randomized, double-blind, multi-center studies (067, 100, 812b, and 058) evaluated clarithromycin 500 mg t.i.d. plus omeprazole 40 mg q.d. for 14 days, followed by omeprazole 20 mg q.d. (067, 100, and 058) or by omeprazole 40 mg q.d. (812b) for an additional 14 days in patients with active duodenal ulcer associated with H. pylori. Studies 067 and 100 were conducted in the U.S. and Canada and enrolled 242 and 256 patients, respectively. H. pylori infection and duodenal ulcer were confirmed in 219 patients in Study 067 and 228 patients in Study 100. These studies compared the combination regimen to omeprazole and clarithromycin monotherapies. Studies 812b and 058 were conducted in Europe and enrolled 154 and 215 patients, respectively. H. pylori infection and duodenal ulcer were confirmed in 148 patients in Study 812b and 208 patients in Study 058. These studies compared the combination regimen to omeprazole monotherapy. The results for the efficacy analyses for these studies are described below. Duodenal Ulcer Healing The combination of clarithromycin and omeprazole was as effective as omeprazole alone for healing duodenal ulcer. End-of-Treatment Ulcer Healing Rates Percent of Patients Healed (n/N) Study Clarithromycin + Omeprazole Omeprazole Clarithromycin U.S. Studies Study 100 94% (58/62) p<0.05 for clarithromycin + omeprazole versus clarithromycin monotherapy. 88% (60/68) 71% (49/69) Study 067 88% (56/64) 85% (55/65) 64% (44/69) Non-U.S. Studies Study 058 99% (84/85) 95% (82/86) N/A Study 812b In Study 812b patients received omeprazole 40 mg daily for days 15 to 28. 100% (64/64) 99% (71/72) N/A Eradication of H. pylori Associated with Duodenal Ulcer The combination of clarithromycin and omeprazole was effective in eradicating H. pylori. H. pylori Eradication Rates (Per-Protocol Analysis) at 4 to 6 weeks Percent of Patients Cured (n/N) Study Clarithromycin + Omeprazole Omeprazole Clarithromycin U.S. Studies Study 100 64% (39/61) Statistically significantly higher than clarithromycin monotherapy (p<0.05) Statistically significantly higher than omeprazole monotherapy (p<0.05). 0% (0/59) 39% (17/44) Study 067 74% (39/53) 0% (0/54) 31% (13/42) Non-U.S. Studies Study 058 74% (64/86) 1% (1/90) N/A Study 812b 83% (50/60) 1% (1/74) N/A H. pylori eradication was defined as no positive test (culture or histology) at 4 weeks following the end of treatment, and two negative tests were required to be considered eradicated. In the per-protocol analysis, the following patients were excluded: dropouts, patients with major protocol violations, patients with missing H. pylori tests post-treatment, and patients that were not assessed for H. pylori eradication at 4 weeks after the end of treatment because they were found to have an unhealed ulcer at the end of treatment. Ulcer recurrence at 6-months following the end of treatment was assessed for patients in whom ulcers were healed post-treatment. Ulcer Recurrence at 6 months by H. pylori Status at 4 to 6 Weeks H. pylori Negative H. pylori Positive U.S. Studies Study 100 Clarithromycin + Omeprazole 6% (2/34) 56% (9/16) Omeprazole – (0/0) 71% (35/49) Clarithromycin 12% (2/17) 32% (7/22) Study 067 Clarithromycin + Omeprazole 38% (11/29) 50% (6/12) Omeprazole – (0/0) 67% (31/46) Clarithromycin 18% (2/11) 52% (14/27) Non-U.S. Studies Study 058 Clarithromycin + Omeprazole 6% (3/53) 24% (4/17) Omeprazole 0% (0/3) 55% (39/71) Study 812b See 12-Month Recurrence Rates. Clarithromycin + Omeprazole 5% (2/42) 0% (0/7) Omeprazole 0% (0/1) 54% (32/59) 12-Month Recurrence Rates Clarithromycin + Omeprazole 3% (1/40) 0% (0/6) Omeprazole 0% (0/1) 67% (29/43) Thus, in patients with duodenal ulcer associated with H. pylori infection, eradication of H. pylori reduced ulcer recurrence. Safety The adverse event profiles for the four studies showed that the combination of clarithromycin 500 mg t.i.d. and omeprazole 40 mg q.d. for 14 days, followed by omeprazole 20 mg q.d. (067, 100, and 058) or 40 mg q.d.(812b) for an additional 14 days was well tolerated. Of the 346 patients who received the combination, 12 (3.5%) patients discontinued study drug due to adverse events. Adverse Events with an Incidence of 3% or Greater Adverse Event Clarithromycin + Omeprazole (n = 346) % of Patients Omeprazole (n = 355) % of Patients Clarithromycin (n = 166) % of Patients Studies 067 and 100, only Taste Perversion 15% 1% 16% Nausea 5% 1% 3% Headache 5% 6% 9% Diarrhea 4% 3% 7% Vomiting 4% <1% 1% Abdominal Pain 3% 2% 1% Infection 3% 4% 2% Most of these events were mild to moderate in severity. Changes in Laboratory Values Changes in laboratory values with possible clinical significance in patients taking clarithromycin and omeprazole were as follows: Hepatic–– elevated direct bilirubin <1%; GGT <1%; SGOT (AST) <1%; SGPT (ALT) <1%. Renal–– elevated serum creatinine <1%. For information on omeprazole, refer to the ADVERSE REACTIONS section of the PRILOSEC package insert. Clarithromycin + Ranitidine Bismuth Citrate Therapy In a U.S. double-blind, randomized, multicenter, dose-comparison trial, ranitidine bismuth citrate 400 mg b.i.d. for 4 weeks plus clarithromycin 500 mg b.i.d. for the first 2 weeks was found to have an equivalent H. pylori eradication rate (based on culture and histology) when compared to ranitidine bismuth citrate 400 mg b.i.d. for 4 weeks plus clarithromycin 500 mg t.i.d. for the first 2 weeks. The intent-to-treat H. pylori eradication rates are shown below: H. pylori Eradication Rates in Study H2BA-3001 Analysis RBC 400 mg + Clarithromycin 500 mg b.i.d. RBC 400 mg + Clarithromycin 500 mg t.i.d 95% CI Rate Difference ITT 65% (122/188) [58%, 72%] 63% (122/195) [55%, 69%] (-8%, 12%) Per-Protocol 72% (117/162) [65%, 79%] 71% (120/170) [63%,77%] (-9%, 12%) H. pylori eradication was defined as no positive test at 4 weeks following the end of treatment. Patients must have had two tests performed, and these must have been negative to be considered eradicated of H. pylori. The following patients were excluded from the per-protocol analysis: patients not infected with H. pylori prestudy, dropouts, patients with major protocol violations, patients with missing H. pylori tests. Patients excluded from the intent-to-treat analysis included those not infected with H. pylori prestudy and those with missing H. pylori tests prestudy. Patients were assessed for H. pylori eradication (4 weeks following treatment) regardless of their healing status (at the end of treatment). The relationship between H. pylori eradication and duodenal ulcer recurrence was assessed in a combined analysis of six U.S. randomized, double-blind, multicenter, placebo-controlled trials using ranitidine bismuth citrate with or without antibiotics. The results from approximately 650 U.S. patients showed that the risk of ulcer recurrence within 6 months of completing treatment was two times less likely in patients whose H. pylori infection was eradicated compared to patients in whom H. pylori infection was not eradicated. Safety In clinical trials using combination therapy with clarithromycin plus ranitidine bismuth citrate, no adverse reactions peculiar to the combination of these drugs (using clarithromycin twice daily or three times a day) were observed. Adverse reactions that have occurred have been limited to those reported with clarithromycin or ranitidine bismuth citrate. (See ADVERSE REACTIONS section of the Tritec package insert.) The most frequent adverse experiences observed in clinical trials using combination therapy with clarithromycin (500 mg three times a day) with ranitidine bismuth citrate (n = 329) were taste disturbance (11%), diarrhea (5%), nausea and vomiting (3%). The most frequent adverse experiences observed in clinical trials using combination therapy with clarithromycin (500 mg twice daily) with ranitidine bismuth citrate (n = 196) were taste disturbance (8%), nausea and vomiting (5%), and diarrhea (4%).
HOW SUPPLIED
Clarithromycin tablets 250 mg are white, oval-shaped, film-coated tablets, debossed GG C6 on one side and plain on the reverse side, and are supplied as follows: NDC 0781-1961-31 in bottles of 30 tablets NDC 0781-1961-60 in bottles of 60 tablets NDC 0781-1961-01 in bottles of 100 tablets NDC 0781-1961-10 in bottles of 1000 tablets Clarithromycin tablets 500 mg are white, oval-shaped, film-coated tablets, debossed GG C9 on one side and plain on the reverse side, and are supplied as follows: NDC 0781-1962-31 in bottles of 30 tablets NDC 0781-1962-60 in bottles of 60 tablets NDC 0781-1962-01 in bottles of 100 tablets NDC 0781-1962-05 in bottles of 500 tablets Store at 20°-25°C (68°-77°F) (see USP Controlled Room Temperature). Dispense in a tight container as described in the USP. Protect from light.
GERIATRIC USE
Geriatric Use In a steady-state study in which healthy elderly subjects (age 65 to 81 years old) were given 500 mg every 12 hours, the maximum serum concentrations and area under the curves of clarithromycin and 14-OH clarithromycin were increased compared to those achieved in healthy young adults. These changes in pharmacokinetics parallel known age-related decreases in renal function. In clinical trials, elderly patients did not have an increased incidence of adverse events when compared to younger patients. Dosage adjustment should be considered in elderly patients with severe renal impairment. Elderly patients may be more susceptible to development of torsades de pointes arrhythmias than younger patients. (See WARNINGS and PRECAUTIONS .)
INDICATIONS AND USAGE
Clarithromycin tablets are indicated for the treatment of mild to moderate infections caused by susceptible isolates of the designated bacteria in the conditions as listed below: Adults Pharyngitis/Tonsillitis due to Streptococcus pyogenes (The usual drug of choice in the treatment and prevention of streptococcal infections and the prophylaxis of rheumatic fever is penicillin administered by either the intramuscular or the oral route. Clarithromycin is generally effective in the eradication of S. pyogenes from the nasopharynx; however, data establishing the efficacy of clarithromycin in the subsequent prevention of rheumatic fever are not available at present.) Acute maxillary sinusitis due to Haemophilusinfluenzae, Moraxella catarrhalis, or Streptococcus pneumoniae Acute bacterial exacerbation of chronic bronchitis due to Haemophilusinfluenzae, Haemophilusparainfluenzae, Moraxella catarrhalis, or Streptococcus pneumoniae Community-Acquired Pneumonia due to Haemophilusinfluenzae, Mycoplasma pneumoniae, Streptococcus pneumoniae, or Chlamydia pneumoniae (TWAR) Uncomplicated skin and skin structure infections due to Staphylococcus aureus, or Streptococcus pyogenes (Abscesses usually require surgical drainage.) Disseminated mycobacterial infections due to Mycobacterium avium, or Mycobacterium intracellulare Clarithromycin tablets in combination with amoxicillin and lansoprazole or omeprazole delayed-release capsules, as triple therapy, are indicated for the treatment of patients with H. pylori infection and duodenal ulcer disease (active or five-year history of duodenal ulcer) to eradicate H. pylori. Clarithromycin tablets in combination with omeprazole capsules or ranitidine bismuth citrate tablets are also indicated for the treatment of patients with an active duodenal ulcer associated with H. pylori infection. However, regimens which contain clarithromycin as the single antimicrobial agent are more likely to be associated with the development of clarithromycin resistance among patients who fail therapy. Clarithromycin-containing regimens should not be used in patients with known or suspected clarithromycin resistant isolates because the efficacy of treatment is reduced in this setting. In patients who fail therapy, susceptibility testing should be done if possible. If resistance to clarithromycin is demonstrated, a non-clarithromycin-containing therapy is recommended. (For information on development of resistance see Microbiology section.) The eradication of H. pylori has been demonstrated to reduce the risk of duodenal ulcer recurrence. Children Pharyngitis/Tonsillitis due to Streptococcus pyogenes Community-Acquired Pneumonia due to Mycoplasma pneumoniae, Streptococcus pneumoniae, or Chlamydia pneumoniae (TWAR) Acute maxillary sinusitis due to Haemophilusinfluenzae, Moraxella catarrhalis, or Streptococcus pneumoniae Acute otitis media due to Haemophilusinfluenzae, Moraxella catarrhalis,or Streptococcus pneumoniae NOTE: For information on otitis media, see CLINICAL STUDIES: Otitis Media . Uncomplicated skin and skin structure infections due to Staphylococcus aureus, or Streptococcus pyogenes (Abscesses usually require surgical drainage.) Disseminated mycobacterial infections due to Mycobacterium avium, or Mycobacterium intracellulare Prophylaxis Clarithromycin tablets are indicated for the prevention of disseminated Mycobacterium avium complex (MAC) disease in patients with advanced HIV infection. To reduce the development of drug-resistant bacteria and maintain the effectiveness of clarithromycin tablets and other antibacterial drugs, clarithromycin tablets should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.
PEDIATRIC USE
Pediatric Use Safety and effectiveness of clarithromycin in pediatric patients under 6 months of age have not been established. The safety of clarithromycin has not been studied in MAC patients under the age of 20 months. Neonatal and juvenile animals tolerated clarithromycin in a manner similar to adult animals. Young animals were slightly more intolerant to acute overdosage and to subtle reductions in erythrocytes, platelets and leukocytes but were less sensitive to toxicity in the liver, kidney, thymus, and genitalia.
PREGNANCY
Pregnancy Teratogenic Effects Pregnancy Category C Four teratogenicity studies in rats (three with oral doses and one with intravenous doses up to 160 mg/kg/day administered during the period of major organogenesis) and two in rabbits at oral doses up to 125 mg/kg/day (approximately 2 times the recommended maximum human dose based on mg/m 2) or intravenous doses of 30 mg/kg/day administered during gestation days 6 to 18 failed to demonstrate any teratogenicity from clarithromycin. Two additional oral studies in a different rat strain at similar doses and similar conditions demonstrated a low incidence of cardiovascular anomalies at doses of 150 mg/kg/day administered during gestation days 6 to 15. Plasma levels after 150 mg/kg/day were 2 times the human serum levels. Four studies in mice revealed a variable incidence of cleft palate following oral doses of 1000 mg/kg/day (2 and 4 times the recommended maximum human dose based on mg/m 2, respectively) during gestation days 6 to 15. Cleft palate was also seen at 500 mg/kg/day. The 1000 mg/kg/day exposure resulted in plasma levels 17 times the human serum levels. In monkeys, an oral dose of 70 mg/kg/day (an approximate equidose of the recommended maximum human dose based on mg/m 2) produced fetal growth retardation at plasma levels that were 2 times the human serum levels. There are no adequate and well-controlled studies in pregnant women. Clarithromycin should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. (See WARNINGS .)
NUSRING MOTHERS
Nursing Mothers It is not known whether clarithromycin is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when clarithromycin is administered to a nursing woman. It is known that clarithromycin is excreted in the milk of lactating animals and that other drugs of this class are excreted in human milk. Preweaned rats, exposed indirectly via consumption of milk from dams treated with 150 mg/kg/day for 3 weeks, were not adversely affected, despite data indicating higher drug levels in milk than in plasma.
BOXED WARNING
Note: When testing Streptococcus pyogenes and Streptococcus pneumoniae, susceptibility and resistance to clarithromycin can be predicted using erythromycin.
DOSAGE AND ADMINISTRATION
Clarithromycin tablets may be given with or without food. Clarithromycin may be administered without dosage adjustment in the presence of hepatic impairment if there is normal renal function. In patients with severe renal impairment (CLCR < 30 mL/min), the dose of clarithromycin should be reduced by 50%. However, when patients with moderate or severe renal impairment are taking clarithromycin concomitantly with atazanavir or ritonavir, the dose of clarithromycin should be reduced by 50% or 75% for patients with CLCR of 30 to 60 mL/min or < 30 mL/min, respectively. ADULT DOSAGE GUIDELINES Clarithromycin Tablets Infection Dosage (q12h) Duration (days) Pharyngitis/Tonsillitis due to S. pyogenes 250 mg 10 Acute maxillary sinusitis due to H. influenzae M. catarrhalis S. pneumoniae 500 mg 14 Acute exacerbation of chronic bronchitis due to H. influenzae 500 mg 7-14 H. parainfluenzae 500 mg 7 M. catarrhalis 250 mg 7-14 S. pneumoniae 250 mg 7-14 Community-Acquired Pneumonia due to H. influenzae 250 mg 7 H. parainfluenzae — — M. catarrhalis — — S. pneumoniae 250 mg 7-14 C. pneumoniae 250 mg 7-14 M. pneumoniae 250 mg 7-14 Uncomplicated skin and skin structure S. aureus S. pyogenes 250 mg 7-14 H. pylori Eradication to Reduce the Risk of Duodenal Ulcer Recurrence Triple Therapy: Clarithromycin/Lansoprazole/Amoxicillin The recommended adult dose is 500 mg clarithromycin, 30 mg lansoprazole, and 1 gram amoxicillin, all given twice daily (q12h) for 10 or 14 days. (See INDICATIONS AND USAGE and CLINICAL STUDIES sections.) Triple Therapy: Clarithromycin/Omeprazole/Amoxicillin The recommended adult dose is 500 mg clarithromycin, 20 mg omeprazole, and 1 gram amoxicillin, all given twice daily (q12h) for 10 days. (See INDICATIONS AND USAGE and CLINICAL STUDIES sections.) In patients with an ulcer present at the time of initiation of therapy, an additional 18 days of omeprazole 20 mg once daily is recommended for ulcer healing and symptom relief. Dual Therapy: Clarithromycin/Omeprazole The recommended adult dose is 500 mg clarithromycin given three times daily (q8h) and 40 mg omeprazole given once daily (qAM) for 14 days. (See INDICATIONS AND USAGE and CLINICAL STUDIES sections.) An additional 14 days of omeprazole 20 mg once daily is recommended for ulcer healing and symptom relief. Dual Therapy: Clarithromycin/Ranitidine Bismuth Citrate The recommended adult dose is 500 mg clarithromycin given twice daily (q12h) or three times daily (q8h) and 400 mg ranitidine bismuth citrate given twice daily (q12h) for 14 days. An additional 14 days of 400 mg twice daily is recommended for ulcer healing and symptom relief. Clarithromycin and ranitidine bismuth citrate combination therapy is not recommended in patients with creatinine clearance less than 25 mL/min. (See INDICATIONS AND USAGE and CLINICAL STUDIES sections.) Children The usual recommended daily dosage is 15 mg/kg/day divided q12h for 10 days. PEDIATRIC DOSAGE GUIDELINES Based on Body Weight Dosing Calculated on 7.5 mg/kg q12h Weight Dose (q12h) kg lbs 9 20 62.5 mg 17 37 125 mg 25 55 187.5 mg 33 73 250 mg Mycobacterial Infections Prophylaxis The recommended dose of clarithromycin for the prevention of disseminated Mycobacterium avium disease is 500 mg b.i.d. In children, the recommended dose is 7.5 mg/kg b.i.d. up to 500 mg b.i.d. No studies of clarithromycin for MAC prophylaxis have been performed in pediatric populations and the doses recommended for prophylaxis are derived from MAC treatment studies in children. Dosing recommendations for children are in the table above. Treatment Clarithromycin is recommended as the primary agent for the treatment of disseminated infection due to Mycobacterium aviumcomplex. Clarithromycin should be used in combination with other antimycobacterial drugs that have shown in vitro activity against MAC or clinical benefit in MAC treatment. (See CLINICAL STUDIES .) The recommended dose for mycobacterial infections in adults is 500 mg b.i.d. In children, the recommended dose is 7.5 mg/kg b.i.d. up to 500 mg b.i.d. Dosing recommendations for children are in the table above. Clarithromycin therapy should continue for life if clinical and mycobacterial improvements are observed.