Azithromycin 500 MG Oral Tablet [Zithromax]

DRUG INTERACTIONS

7 Nelfinavir: Close monitoring for known adverse reactions of azithromycin, such as liver enzyme abnormalities and hearing impairment, is warranted.

( 7.1 ) Warfarin: Use with azithromycin may increase coagulation times; monitor prothrombin time.

( 7.2 ) 7.1 Nelfinavir Co-administration of nelfinavir at steady-state with a single oral dose of azithromycin resulted in increased azithromycin serum concentrations.

Although a dose adjustment of azithromycin is not recommended when administered in combination with nelfinavir, close monitoring for known adverse reactions of azithromycin, such as liver enzyme abnormalities and hearing impairment, is warranted.

[see Adverse Reactions (6) ] 7.2 Warfarin Spontaneous postmarketing reports suggest that concomitant administration of azithromycin may potentiate the effects of oral anticoagulants such as warfarin, although the prothrombin time was not affected in the dedicated drug interaction study with azithromycin and warfarin.

Prothrombin times should be carefully monitored while patients are receiving azithromycin and oral anticoagulants concomitantly.

7.

3 Potential Drug-Drug Interactions with Macrolides Interactions with digoxin or phenytoin have not been reported in clinical trials with azithromycin; however, no specific drug interaction studies have been performed to evaluate potential drug-drug interactions.

However, drug interactions have been observed with other macrolide products.

Until further data are developed regarding drug interactions when digoxin or phenytoin are used concomitantly with azithromycin careful monitoring of patients is advised.

OVERDOSAGE

10 Adverse reactions experienced at higher than recommended doses were similar to those seen at normal doses particularly nausea, diarrhea, and vomiting.

In the event of overdosage, general symptomatic and supportive measures are indicated as required.

DESCRIPTION

11 ZITHROMAX (azithromycin tablets and azithromycin for oral suspension) contain the active ingredient azithromycin, a macrolide antibacterial drug, for oral administration.

Azithromycin has the chemical name (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-dideoxy-3-C-methyl-3-O-methyl-α-L-ribo-hexopyranosyl) oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,12,14-heptamethyl-11-[[3,4,6-trideoxy-3-(dimethylamino)-β-D-xylo-hexopyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one.

Azithromycin is derived from erythromycin; however, it differs chemically from erythromycin in that a methyl-substituted nitrogen atom is incorporated into the lactone ring.

Its molecular formula is C38H72N2O12, and its molecular weight is 749.00.

Azithromycin has the following structural formula: Azithromycin, as the dihydrate, is a white crystalline powder with a molecular formula of C38H72N2O12∙2H2O and a molecular weight of 785.0.

ZITHROMAX is supplied as tablets containing azithromycin dihydrate equivalent to either 250 mg or 500 mg azithromycin and the following inactive ingredients: dibasic calcium phosphate anhydrous, pregelatinized starch, sodium croscarmellose, magnesium stearate, sodium lauryl sulfate, hypromellose, lactose, titanium dioxide, triacetin, and D&C Red #30 aluminum lake.

ZITHROMAX for oral suspension is supplied in bottles containing azithromycin dihydrate powder equivalent to 300 mg, 600 mg, 900 mg, or 1200 mg azithromycin per bottle and the following inactive ingredients: sucrose; sodium phosphate, tribasic, anhydrous; hydroxypropyl cellulose; xanthan gum; FD&C Red #40; and spray dried artificial cherry, creme de vanilla, and banana flavors.

After constitution, each 5 mL of suspension contains 100 mg or 200 mg of azithromycin.

Chemical Structure

CLINICAL STUDIES

14 14.1 Adult Patients Acute Bacterial Exacerbations of Chronic Bronchitis In a randomized, double-blind controlled clinical trial of acute exacerbation of chronic bronchitis (AECB), azithromycin (500 mg once daily for 3 days) was compared with clarithromycin (500 mg twice daily for 10 days).

The primary endpoint of this trial was the clinical cure rate at Days 21– 24.

For the 304 patients analyzed in the modified intent-to-treat analysis at the Days 21–24 visit, the clinical cure rate for 3 days of azithromycin was 85% (125/147) compared to 82% (129/157) for 10 days of clarithromycin.

The following outcomes were the clinical cure rates at the Days 21–24 visit for the bacteriologically evaluable patients by pathogen: Pathogen Azithromycin (3 Days) Clarithromycin (10 Days) S.

pneumoniae 29/32 (91%) 21/27 (78%) H.

influenzae 12/14 (86%) 14/16 (88%) M.

catarrhalis 11/12 (92%) 12/15 (80%) Acute Bacterial Sinusitis In a randomized, double-blind, double-dummy controlled clinical trial of acute bacterial sinusitis, azithromycin (500 mg once daily for 3 days) was compared with amoxicillin/clavulanate (500/125 mg three times a day for 10 days).

Clinical response assessments were made at Day 10 and Day 28.

The primary endpoint of this trial was prospectively defined as the clinical cure rate at Day 28.

For the 594 patients analyzed in the modified intent to treat analysis at the Day 10 visit, the clinical cure rate for 3 days of azithromycin was 88% (268/303) compared to 85% (248/291) for 10 days of amoxicillin/clavulanate.

For the 586 patients analyzed in the modified intent to treat analysis at the Day 28 visit, the clinical cure rate for 3 days of azithromycin was 71.5% (213/298) compared to 71.5% (206/288), with a 97.5% confidence interval of –8.4 to 8.3, for 10 days of amoxicillin/clavulanate.

In an open label, non-comparative study requiring baseline transantral sinus punctures, the following outcomes were the clinical success rates at the Day 7 and Day 28 visits for the modified intent to treat patients administered 500 mg of azithromycin once daily for 3 days with the following pathogens: Clinical Success Rates of Azithromycin (500 mg per day for 3 Days) Pathogen Day 7 Day28 S.

pneumoniae 23/26 (88%) 21/25 (84%) H.

influenzae 28/32 (87%) 24/32 (75%) M.

catarrhalis 14/15 (93%) 13/15 (87%) 14.2 Pediatric Patients From the perspective of evaluating pediatric clinical trials, Days 11–14 were considered on-therapy evaluations because of the extended half-life of azithromycin.

Days 11–14 data are provided for clinical guidance.

Days 24–32 evaluations were considered the primary test of cure endpoint.

Pharyngitis/Tonsillitis In three double-blind controlled studies, conducted in the United States, azithromycin (12 mg/kg once a day for 5 days) was compared to penicillin V (250 mg three times a day for 10 days) in the treatment of pharyngitis due to documented Group A β-hemolytic streptococci (GABHS or S.

pyogenes ).

Azithromycin was clinically and microbiologically statistically superior to penicillin at Day 14 and Day 30 with the following clinical success (i.e., cure and improvement) and bacteriologic efficacy rates (for the combined evaluable patient with documented GABHS): Three U.S.

Streptococcal Pharyngitis Studies Azithromycin vs.

Penicillin V EFFICACY RESULTS Day 14 Day 30 Bacteriologic Eradication: Azithromycin 323/340 (95%) 255/330 (77%) Penicillin V 242/332 (73%) 206/325 (63%) Clinical Success (cure plus improvement): Azithromycin 336/343 (98%) 310/330 (94%) Penicillin V 284/338 (84%) 241/325 (74%) Approximately 1% of azithromycin-susceptible S.

pyogenes isolates were resistant to azithromycin following therapy.

Acute Otitis Media Efficacy using azithromycin given over 5 days (10 mg/kg on Day 1 followed by 5 mg/kg on Days 2–5).

Trial 1 In a double-blind, controlled clinical study of acute otitis media performed in the United States, azithromycin (10 mg/kg on Day 1 followed by 5 mg/kg on Days 2–5) was compared to amoxicillin/clavulanate potassium (4:1).

For the 553 patients who were evaluated for clinical efficacy, the clinical success rate (i.e., cure plus improvement) at the Day 11 visit was 88% for azithromycin and 88% for the control agent.

For the 521 patients who were evaluated at the Day 30 visit, the clinical success rate was 73% for azithromycin and 71% for the control agent.

Trial 2 In a non-comparative clinical and microbiologic trial performed in the United States, where significant rates of beta-lactamase producing organisms (35%) were found, 131 patients were evaluable for clinical efficacy.

The combined clinical success rate (i.e., cure and improvement) at the Day 11 visit was 84% for azithromycin.

For the 122 patients who were evaluated at the Day 30 visit, the clinical success rate was 70% for azithromycin.

Microbiologic determinations were made at the pre-treatment visit.

Microbiology was not reassessed at later visits.

The following clinical success rates were obtained from the evaluable group: Pathogen Day 11 Day 30 Azithromycin Azithromycin S.

pneumoniae 61/74 (82%) 40/56 (71%) H.

influenzae 43/54 (80%) 30/47 (64%) M.

catarrhalis 28/35 (80%) 19/26 (73%) S.

pyogenes 11/11 (100%) 7/7 (100%) Overall 177/217 (82%) 97/137 (73%) Trial 3 In another controlled comparative clinical and microbiologic study of otitis media performed in the United States, azithromycin (10 mg/kg on Day 1 followed by 5 mg/kg on Days 2–5).was compared to amoxicillin/clavulanate potassium (4:1).

This study utilized two of the same investigators as Protocol 2 (above), and these two investigators enrolled 90% of the patients in Protocol 3.

For this reason, Protocol 3 was not considered to be an independent study.

Significant rates of beta-lactamase producing organisms (20%) were found.

Ninety-two (92) patients were evaluable for clinical and microbiologic efficacy.

The combined clinical success rate (i.e., cure and improvement) of those patients with a baseline pathogen at the Day 11 visit was 88% for azithromycin vs.

100% for control; at the Day 30 visit, the clinical success rate was 82% for azithromycin vs.

80% for control.

Microbiologic determinations were made at the pre-treatment visit.

Microbiology was not reassessed at later visits.

At the Day 11 and Day 30 visits, the following clinical success rates were obtained from the evaluable group: Day 11 Day 30 Pathogen Azithromycin Control Azithromycin Control S.

pneumoniae 25/29 (86%) 26/26 (100%) 22/28 (79%) 18/22 (82%) H.

influenzae 9/11 (82%) 9/9 (100%) 8/10 (80%) 6/8 (75%) M.

catarrhalis 7/7 (100%) 5/5 (100%) 5/5 (100%) 2/3 (66%) S.

pyogenes 2/2 (100%) 5/5 (100%) 2/2 (100%) 4/4 (100%) Overall 43/49 (88%) 45/45 (100%) 37/45 (82%) 30/37 (81%) Efficacy using azithromycin given over 3 days (10 mg/kg/day).

Trial 4 In a double-blind, controlled, randomized clinical study of acute otitis media in pediatric patients from 6 months to 12 years of age, azithromycin (10 mg/kg per day for 3 days) was compared to amoxicillin/clavulanate potassium (7:1) in divided doses q12h for 10 days.

Each patient received active drug and placebo matched for the comparator.

For the 366 patients who were evaluated for clinical efficacy at the Day 12 visit, the clinical success rate (i.e., cure plus improvement) was 83% for azithromycin and 88% for the control agent.

For the 362 patients who were evaluated at the Days 24–28 visit, the clinical success rate was 74% for azithromycin and 69% for the control agent.

Efficacy using azithromycin 30 mg/kg given as a single dose Trial 5 A double-blind, controlled, randomized trial was performed at nine clinical centers.

Pediatric patients from 6 months to 12 years of age were randomized 1:1 to treatment with either azithromycin (given at 30 mg/kg as a single dose on Day 1) or amoxicillin/clavulanate potassium (7:1), divided q12h for 10 days.

Each child received active drug, and placebo matched for the comparator.

Clinical response (Cure, Improvement, Failure) was evaluated at End of Therapy (Days 12–16) and Test of Cure (Days 28–32).

Safety was evaluated throughout the trial for all treated subjects.

For the 321 subjects who were evaluated at End of Treatment, the clinical success rate (cure plus improvement) was 87% for azithromycin, and 88% for the comparator.

For the 305 subjects who were evaluated at Test of Cure, the clinical success rate was 75% for both azithromycin and the comparator.

Trial 6 In a non-comparative clinical and microbiological trial, 248 patients from 6 months to 12 years of age with documented acute otitis media were dosed with a single oral dose of azithromycin (30 mg/kg on Day 1).

For the 240 patients who were evaluable for clinical modified Intent-to-Treat (MITT) analysis, the clinical success rate (i.e., cure plus improvement) at Day 10 was 89% and for the 242 patients evaluable at Days 24–28, the clinical success rate (cure) was 85%.

Presumed Bacteriologic Eradication Day 10 Days 24–28 S.

pneumoniae 70/76 (92%) 67/76 (88%) H.

influenzae 30/42 (71%) 28/44 (64%) M.

catarrhalis 10/10 (100%) 10/10 (100%) Overall 110/128 (86%) 105/130 (81%)

HOW SUPPLIED

16 /STORAGE AND HANDLING ZITHROMAX is supplied in the following strengths and package configurations: ZITHROMAX 250 mg tablets are supplied as pink modified capsular shaped, engraved, film-coated tablets containing azithromycin dihydrate equivalent to 250 mg of azithromycin.

ZITHROMAX 250 mg tablets are engraved with “PFIZER” on one side and “306” on the other.

These are packaged in bottles and blister cards of 6 tablets (Z-PAKS ® ) as follows: Bottles of 30 NDC 0069-3060-30 Boxes of 3 (Z-PAKS ® of 6) NDC 0069-3060-75 Unit Dose package of 50 NDC 0069-3060-86 ZITHROMAX 500 mg tablets are supplied as pink modified capsular shaped, engraved, film-coated tablets containing azithromycin dihydrate equivalent to 500 mg of azithromycin.

ZITHROMAX 500 mg tablets are engraved with “Pfizer” on one side and “ZTM500” on the other.

These are packaged in bottles and blister cards of 3 tablets (TRI-PAKS™) as follows: Bottles of 30 NDC 0069-3070-30 Boxes of 3 (TRI-PAKS™ of 3 tablets) NDC 0069-3070-75 Unit Dose package of 50 NDC 0069-3070-86 ZITHROMAX tablets should be stored between 15° to 30°C (59° to 86°F).

ZITHROMAX for oral suspension after constitution contains a flavored suspension.

ZITHROMAX for oral suspension is supplied to provide 100 mg/5 mL or 200 mg/5 mL suspension in bottles as follows: Azithromycin contents per bottle NDC 300 mg 0069-3110-19 600 mg 0069-3120-19 900 mg 0069-3130-19 1200 mg 0069-3140-19 [see Dosage and Administration (2) ] for constitution instructions with each bottle type.

Storage: Store dry powder below 30°C (86°F).

Store constituted suspension between 5° to 30°C (41° to 86°F) and discard when full dosing is completed.

RECENT MAJOR CHANGES

Warnings and Precautions, Hypersensitivity ( 5.1 ) 5/2016

GERIATRIC USE

8.5 Geriatric Use In multiple-dose clinical trials of oral azithromycin, 9% of patients were at least 65 years of age (458/4949) and 3% of patients (144/4949) were at least 75 years of age.

No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in response between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.

Elderly patients may be more susceptible to development of torsades de pointes arrhythmias than younger patients.

[see Warnings and Precautions (5.3) ]

DOSAGE FORMS AND STRENGTHS

3 ZITHROMAX 250 mg tablets are supplied as pink modified capsular shaped, engraved, film-coated tablets containing azithromycin dihydrate equivalent to 250 mg of azithromycin.

ZITHROMAX 250 mg tablets are engraved with “PFIZER” on one side and “306” on the other.

These are packaged in bottles and blister cards of 6 tablets (Z-PAKS ® ).

ZITHROMAX 500 mg tablets are supplied as pink modified capsular shaped, engraved, film-coated tablets containing azithromycin dihydrate equivalent to 500 mg of azithromycin.

ZITHROMAX 500 mg tablets are engraved with “Pfizer” on one side and “ZTM500” on the other.

These are packaged in bottles and blister cards of 3 tablets (TRI-PAKS™).

ZITHROMAX for oral suspension after constitution contains a flavored suspension.

ZITHROMAX for oral suspension is supplied to provide 100 mg/5 mL or 200 mg/5 mL suspension in bottles.

ZITHROMAX tablets 250 mg and 500 mg ( 3 ) ZITHROMAX for oral suspension 100 mg/5 mL and 200 mg/5 mL ( 3 )

MECHANISM OF ACTION

12.1 Mechanism of Action Azithromycin is a macrolide antibacterial drug.

[see Microbiology (12.4) ]

INDICATIONS AND USAGE

1 To reduce the development of drug-resistant bacteria and maintain the effectiveness of ZITHROMAX (azithromycin) and other antibacterial drugs, ZITHROMAX (azithromycin) should be used only to treat 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.

ZITHROMAX (azithromycin) is a macrolide antibacterial drug indicated for the treatment of patients with mild to moderate infections caused by susceptible strains of the designated microorganisms in the specific conditions listed below.

Recommended dosages and durations of therapy in adult and pediatric patient populations vary in these indications.

[see Dosage and Administration (2) ] ZITHROMAX is a macrolide antibacterial drug indicated for mild to moderate infections caused by designated, susceptible bacteria: Acute bacterial exacerbations of chronic bronchitis in adults ( 1.1 ) Acute bacterial sinusitis in adults ( 1.1 ) Uncomplicated skin and skin structure infections in adults ( 1.1 ) Urethritis and cervicitis in adults ( 1.1 ) Genital ulcer disease in men ( 1.1 ) Acute otitis media in pediatric patients ( 1.2 ) Community-acquired pneumonia in adults and pediatric patients ( 1.1 , 1.2 ) Pharyngitis/tonsillitis in adults and pediatric patients ( 1.1 , 1.2 ) Limitation of Use: Azithromycin should not be used in patients with pneumonia who are judged to be inappropriate for oral therapy because of moderate to severe illness or risk factors.

( 1.3 ) To reduce the development of drug-resistant bacteria and maintain the effectiveness of ZITHROMAX (azithromycin) and other antibacterial drugs, ZITHROMAX (azithromycin) should be used only to treat infections that are proven or strongly suspected to be caused by susceptible bacteria.

1.1 Adult Patients Acute bacterial exacerbations of chronic bronchitis due to Haemophilus influenzae , Moraxella catarrhalis, or Streptococcus pneumoniae .

Acute bacterial sinusitis due to Haemophilus influenzae , Moraxella catarrhalis.

or Streptococcus pneumoniae .

Community-acquired pneumonia due to Chlamydophila pneumoniae , Haemophilus influenzae , Mycoplasma pneumoniae, or Streptococcus pneumoniae in patients appropriate for oral therapy.

Pharyngitis/tonsillitis caused by Streptococcus pyogenes as an alternative to first-line therapy in individuals who cannot use first-line therapy.

Uncomplicated skin and skin structure infections due to Staphylococcus aureus , Streptococcus pyogenes , or Streptococcus agalactiae .

Urethritis and cervicitis due to Chlamydia trachomatis or Neisseria gonorrhoeae .

Genital ulcer disease in men due to Haemophilus ducreyi (chancroid).

Due to the small number of women included in clinical trials, the efficacy of azithromycin in the treatment of chancroid in women has not been established.

1.2 Pediatric Patients [see Use in Specific Populations (8.4) and Clinical Studies (14.2) ] Acute otitis media ( >6 months of age) c aused by Haemophilus influenzae , Moraxella catarrhalis, or Streptococcus pneumoniae Community-acquired pneumonia ( >6 months of age) due to Chlamydophila pneumoniae , Haemophilus influenzae , Mycoplasma pneumonia , or Streptococcus pneumoniae in patients appropriate for oral therapy.

Pharyngitis/tonsillitis ( > 2 years of age ) caused by Streptococcus pyogenes as an alternative to first-line therapy in individuals who cannot use first-line therapy.

1.3 Limitations of Use Azithromycin should not be used in patients with pneumonia who are judged to be inappropriate for oral therapy because of moderate to severe illness or risk factors such as any of the following: patients with cystic fibrosis, patients with nosocomial infections, patients with known or suspected bacteremia, patients requiring hospitalization, elderly or debilitated patients, or patients with significant underlying health problems that may compromise their ability to respond to their illness (including immunodeficiency or functional asplenia).

PEDIATRIC USE

8.4 Pediatric Use [see Clinical Pharmacology (12.3) , Indications and Usage (1.2) , and Dosage and Administration (2.2) ] Safety and effectiveness in the treatment of pediatric patients with acute otitis media, acute bacterial sinusitis and community-acquired pneumonia under 6 months of age have not been established.

Use of ZITHROMAX for the treatment of acute bacterial sinusitis and community-acquired pneumonia in pediatric patients (6 months of age or greater) is supported by adequate and well-controlled trials in adults Pharyngitis/Tonsillitis: Safety and effectiveness in the treatment of pediatric patients with pharyngitis/tonsillitis under 2 years of age have not been established.

PREGNANCY

8.1 Pregnancy Teratogenic Effects: Pregnancy Category B: Reproduction studies have been performed in rats and mice at doses up to moderately maternally toxic dose concentrations (i.e., 200 mg/kg/day).

These daily doses in rats and mice, based on body surface area, are estimated to be 4 and 2 times, respectively, an adult daily dose of 500 mg.

In the animal studies, no evidence of harm to the fetus due to azithromycin was found.

There are, however, no adequate and well-controlled studies in pregnant women.

Because animal reproduction studies are not always predictive of human response, azithromycin should be used during pregnancy only if clearly needed.

NUSRING MOTHERS

8.3 Nursing Mothers Azithromycin has been reported to be excreted in human breast milk in small amounts.

Caution should be exercised when azithromycin is administered to a nursing woman.

WARNING AND CAUTIONS

5 WARNINGS AND PRECAUTIONS Serious (including fatal) allergic and skin reactions: Discontinue ZITHROMAX if reaction occurs.

( 5.1 ) Hepatotoxicity: Severe, and sometimes fatal, hepatotoxicity has been reported, Discontinue ZITHROMAX immediately if signs and symptoms of hepatitis occur.

( 5.2 ) Prolongation of QT interval and cases of torsades de pointes have been reported.

This risk which can be fatal should be considered in patients with certain cardiovascular disorders including known QT prolongation or history torsades de pointes, those with proarrhythmic conditions, and with other drugs that prolong the QT interval.

( 5.3 ) Clostridium difficile -associated diarrhea: Evaluate patients if diarrhea occurs.

( 5.4 ) ZITHROMAX may exacerbate muscle weakness in persons with myasthenia gravis.

( 5.5 ) 5.1 Hypersensitivity Serious allergic reactions, including angioedema, anaphylaxis, and dermatologic reactions including Stevens-Johnson syndrome, and toxic epidermal necrolysis have been reported in patients on azithromycin therapy.

[see Contraindications (4.1) ] Fatalities have been reported.

Cases of Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) have also been reported.

Despite initially successful symptomatic treatment of the allergic symptoms, when symptomatic therapy was discontinued, the allergic symptoms recurred soon thereafter in some patients without further azithromycin exposure.

These patients required prolonged periods of observation and symptomatic treatment.

The relationship of these episodes to the long tissue half-life of azithromycin and subsequent prolonged exposure to antigen is presently unknown.

If an allergic reaction occurs, the drug should be discontinued and appropriate therapy should be instituted.

Physicians should be aware that allergic symptoms may reappear when symptomatic therapy has been discontinued.If an allergic reaction occurs, the drug should be discontinued and appropriate therapy should be instituted.

Physicians should be aware that allergic symptoms may reappear when symptomatic therapy has been discontinued.

5.2 Hepatotoxicity Abnormal liver function, hepatitis, cholestatic jaundice, hepatic necrosis, and hepatic failure have been reported, some of which have resulted in death.

Discontinue azithromycin immediately if signs and symptoms of hepatitis occur.

5.3 QT Prolongation Prolonged cardiac repolarization and QT interval, imparting a risk of developing cardiac arrhythmia and torsades de pointes, have been seen with treatment with macrolides, including azithromycin.

Cases of torsades de pointes have been spontaneously reported during postmarketing surveillance in patients receiving azithromycin.

Providers should consider the risk of QT prolongation which can be fatal when weighing the risks and benefits of azithromycin for at-risk groups including: patients with known prolongation of the QT interval, a history of torsades de pointes, congenital long QT syndrome, bradyarrhythmias or uncompensated heart failure patients on drugs known to prolong the QT interval patients with ongoing proarrhythmic conditions such as uncorrected hypokalemia or hypomagnesemia, clinically significant bradycardia, 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.

5.4 Clostridium difficile -Associated Diarrhea (CDAD) Clostridium difficile -associated diarrhea has been reported with use of nearly all antibacterial agents, including ZITHROMAX, 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 antibacterial 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.

5.5 Exacerbation of Myasthenia Gravis Exacerbation of symptoms of myasthenia gravis and new onset of myasthenic syndrome have been reported in patients receiving azithromycin therapy.

5.6 Use in Sexually Transmitted Infections ZITHROMAX, at the recommended dose, should not be relied upon to treat syphilis.

Antibacterial agents used to treat non-gonococcal urethritis may mask or delay the symptoms of incubating syphilis.

All patients with sexually transmitted urethritis or cervicitis should have a serologic test for syphilis and appropriate testing for gonorrhea performed at the time of diagnosis.

Appropriate antibacterial therapy and follow-up tests for these diseases should be initiated if infection is confirmed.

5.7 Development of Drug-Resistant Bacteria Prescribing ZITHROMAX in the absence of a proven or strongly suspected bacterial infection is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.

INFORMATION FOR PATIENTS

17 PATIENT COUNSELING INFORMATION General Patient Counseling ZITHROMAX tablets and oral suspension can be taken with or without food.

Patients should also be cautioned not to take aluminum- and magnesium-containing antacids and azithromycin simultaneously.

The patient should be directed to discontinue azithromycin immediately and contact a physician if any signs of an allergic reaction occur.

Patients should be counseled that antibacterial drugs including ZITHROMAX (azithromycin) should only be used to treat bacterial infections.

They do not treat viral infections (e.g., the common cold).

When ZITHROMAX (azithromycin) is prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of the therapy, the medication should be taken exactly as directed.

Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by ZITHROMAX (azithromycin) or other antibacterial drugs in the future.

Diarrhea is a common problem caused by antibacterials which usually ends when the antibacterial is discontinued.

Sometimes after starting treatment with antibacterials patients can develop watery and bloody stools (with or without stomach cramps and fever) even as late as two or more months after having taken the last dose of the antibacterial drug.

If this occurs, patients should contact their physician as soon as possible.

See FDA-approved Patient Labeling Licensed from Pliva LAB-0023-16.0

DOSAGE AND ADMINISTRATION

2 Adult Patients ( 2.1 ) Infection Recommended Dose/Duration of Therapy Community-acquired pneumonia (mild severity) Pharyngitis/tonsillitis (second-line therapy) Skin/skin structure (uncomplicated) 500 mg as a single dose on Day 1, followed by 250 mg once daily on Days 2 through 5.

Acute bacterial exacerbations of chronic bronchitis (mild to moderate) 500 mg as a single dose on Day 1, followed by 250 mg once daily on Days 2 through 5 or 500 mg once daily for 3 days.

Acute bacterial sinusitis 500 mg once daily for 3 days.

Genital ulcer disease (chancroid) Non-gonococcal urethritis and cervicitis One single 1 gram dose.

Gonococcal urethritis and cervicitis One single 2 gram dose.

Pediatric Patients ( 2.2 ) Infection Recommended Dose/Duration of Therapy Acute otitis media 30 mg/kg as a single dose or 10 mg/kg once daily for 3 days or 10 mg/kg as a single dose on Day 1 followed by 5 mg/kg/day on Days 2 through 5.

Acute bacterial sinusitis 10 mg/kg once daily for 3 days.

Community-acquired pneumonia 10 mg/kg as a single dose on Day 1 followed by 5 mg/kg once daily on Days 2 through 5.

Pharyngitis/tonsillitis 12 mg/kg once daily for 5 days.

2.1 Adult Patients [see Indications and Usage (1.1) and Clinical Pharmacology (12.3) ] Infection DUE TO THE INDICATED ORGANISMS [see Indications and Usage (1.1)] Recommended Dose/Duration of Therapy Community-acquired pneumonia Pharyngitis/tonsillitis (second-line therapy) Skin/skin structure (uncomplicated) 500 mg as a single dose on Day 1, followed by 250 mg once daily on Days 2 through 5 Acute bacterial exacerbations of chronic obstructive pulmonary disease 500 mg once daily for 3 days OR 500 mg as a single dose on Day 1, followed by 250 mg once daily on Days 2 through 5 Acute bacterial sinusitis 500 mg once daily for 3 days Genital ulcer disease (chancroid) One single 1 gram dose Non-gonococcal urethritis and cervicitis One single 1 gram dose Gonococcal urethritis and cervicitis One single 2 gram dose ZITHROMAX tablets can be taken with or without food.

2.2 Pediatric Patients 1 Infection DUE TO THE INDICATED ORGANISMS [see Indications and Usage (1.2)] Recommended Dose/Duration of Therapy 1 see dosing tables below for maximum doses evaluated by indication Acute otitis media 30 mg/kg as a single dose or 10 mg/kg once daily for 3 days or 10 mg/kg as a single dose on Day 1 followed by 5 mg/kg/day on Days 2 through 5.

Acute bacterial sinusitis 10 mg/kg once daily for 3 days.

Community-acquired pneumonia 10 mg/kg as a single dose on Day 1 followed by 5 mg/kg once daily on Days 2 through 5.

Pharyngitis/tonsillitis 12 mg/kg once daily for 5 days.

ZITHROMAX for oral suspension can be taken with or without food.

PEDIATRIC DOSAGE GUIDELINES FOR OTITIS MEDIA, ACUTE BACTERIAL SINUSITIS, AND COMMUNITY-ACQUIRED PNEUMONIA (Age 6 months and above, [see Use in Specific Populations (8.4) ] ) Based on Body Weight OTITIS MEDIA AND COMMUNITY-ACQUIRED PNEUMONIA: (5-Day Regimen) Effectiveness of the 3-day or 1-day regimen in pediatric patients with community-acquired pneumonia has not been established.

Dosing Calculated on 10 mg/kg/day Day 1 and 5 mg/kg/day Days 2 to 5.

Weight 100 mg/5 mL 200 mg/5 mL Total mL per Treatment Course Total mg per Treatment Course Kg Lbs.

Day 1 Days 2–5 Day 1 Days 2–5 5 11 2.5 mL; (½ tsp) 1.25 mL;(¼ tsp) 7.5 mL 150 mg 10 22 5 mL; (1tsp) 2.5 mL; (½ tsp) 15 mL 300 mg 20 44 5 mL; (1 tsp) 2.5 mL; (½ tsp) 15 mL 600 mg 30 66 7.5 mL; (1½ tsp) 3.75 mL; (¾ tsp) 22.5 mL 900 mg 40 88 10 mL; (2 tsp) 5 mL; (1 tsp) 30 mL 1200 mg 50 and above 110 and above 12.5 mL; (2½ tsp) 6.25 mL; (1¼ tsp) 37.5 mL 1500 mg OTITIS MEDIA AND ACUTE BACTERIAL SINUSITIS: (3-Day Regimen) Effectiveness of the 5-day or 1-day regimen in pediatric patients with acute bacterial sinusitis has not been established.

Dosing Calculated on 10 mg/kg/day.

Weight 100 mg/5 mL 200 mg/5 mL Total mL per Treatment Course Total mg per Treatment Course Kg Lbs.

Days 1–3 Days 1–3 5 11 2.5 mL; (1/2 tsp) 7.5 mL 150 mg 10 22 5 mL; (1 tsp) 15 mL 300 mg 20 44 5 mL (1 tsp) 15 mL 600 mg 30 66 7.5 mL (1½ tsp) 22.5 mL 900 mg 40 88 10 mL (2 tsp) 30 mL 1200 mg 50 and above 110 and above 12.5 mL (2 ½ tsp) 37.5 mL 1500 mg OTITIS MEDIA: (1-Day Regimen) Dosing Calculated on 30 mg/kg as a single dose.

Weight 200 mg/5 mL Total mL per Treatment Course Total mg per Treatment Course Kg Lbs.

1-Day Regimen 5 11 3.75 mL;(3/4 tsp) 3.75 mL 150 mg 10 22 7.5 mL;(1½ tsp) 7.5 mL 300 mg 20 44 15 mL;(3 tsp) 15 mL 600 mg 30 66 22.5 mL;(4½ tsp) 22.5 mL 900 mg 40 88 30 mL;(6 tsp) 30 mL 1200 mg 50 and above 110 and above 37.5 mL;(7½ tsp) 37.5 mL 1500 mg The safety of re-dosing azithromycin in pediatric patients who vomit after receiving 30 mg/kg as a single dose has not been established.

In clinical studies involving 487 patients with acute otitis media given a single 30 mg/kg dose of azithromycin, 8 patients who vomited within 30 minutes of dosing were re-dosed at the same total dose.

Pharyngitis/Tonsillitis: The recommended dose of ZITHROMAX for children with pharyngitis/tonsillitis is 12 mg/kg once daily for 5 days.

(See chart below.) PEDIATRIC DOSAGE GUIDELINES FOR PHARYNGITIS/TONSILLITIS (Age 2 years and above, [see Use in Specific Populations (8.4) ] ) Based on Body Weight PHARYNGITIS/TONSILLITIS: (5-Day Regimen) Dosing Calculated on 12 mg/kg/day for 5 days.

Weight 200 mg/5 mL Total mL per Treatment Course Total mg per Treatment Course Kg Lbs.

Day 1–5 8 18 2.5 mL; (½ tsp) 12.5 mL 500 mg 17 37 5 mL; (1 tsp) 25 mL 1000 mg 25 55 7.5 mL; (1½ tsp) 37.5 mL 1500 mg 33 73 10 mL; (2 tsp) 50 mL 2000 mg 40 88 12.5 mL; (2½ tsp) 62.5 mL 2500 mg Constituting instructions for ZITHROMAX Oral Suspension 300, 600, 900, 1200 mg bottles.

The table below indicates the volume of water to be used for constitution: Amount of water to be added Total volume after constitution (azithromycin content) Azithromycin concentration after constitution 9 mL (300 mg) 15 mL (300 mg) 100 mg/5 mL 9 mL (600 mg) 15 mL (600 mg) 200 mg/5 mL 12 mL (900 mg) 22.5 mL (900 mg) 200 mg/5 mL 15 mL (1200 mg) 30 mL (1200 mg) 200 mg/5 mL Shake well before each use.

Oversized bottle provides shake space.

Keep tightly closed.

After mixing, store suspension at 5° to 30°C (41° to 86°F) and use within 10 days.

Discard after full dosing is completed.