Norvasc (as amlodipine besylate) 10 MG Oral Tablet

Generic Name: AMLODIPINE BESYLATE
Brand Name: Norvasc
  • Substance Name(s):
  • AMLODIPINE BESYLATE

DRUG INTERACTIONS

7 7.1 In Vitro Data In vitro data indicate that NORVASC has no effect on the human plasma protein binding of digoxin, phenytoin, warfarin, and indomethacin. 7.2 Cimetidine Co-administration of NORVASC with cimetidine did not alter the pharmacokinetics of NORVASC. 7.3 Grapefruit Juice Co-administration of 240 mL of grapefruit juice with a single oral dose of amlodipine 10 mg in 20 healthy volunteers had no significant effect on the pharmacokinetics of amlodipine. 7.4 Magnesium and Aluminum Hydroxide Antacid Co-administration of a magnesium and aluminum hydroxide antacid with a single dose of NORVASC had no significant effect on the pharmacokinetics of NORVASC. 7.5 Sildenafil A single 100 mg dose of sildenafil in subjects with essential hypertension had no effect on the pharmacokinetic parameters of NORVASC. When NORVASC and sildenafil were used in combination, each agent independently exerted its own blood pressure lowering effect. 7.6 Atorvastatin Co-administration of multiple 10 mg doses of NORVASC with 80 mg of atorvastatin resulted in no significant change in the steady-state pharmacokinetic parameters of atorvastatin. 7.7 Digoxin Co-administration of NORVASC with digoxin did not change serum digoxin levels or digoxin renal clearance in normal volunteers. 7.8 Ethanol (Alcohol) Single and multiple 10 mg doses of NORVASC had no significant effect on the pharmacokinetics of ethanol. 7.9 Warfarin Co-administration of NORVASC with warfarin did not change the warfarin prothrombin response time. 7.10 CYP3A4 Inhibitors Co-administration of a 180 mg daily dose of diltiazem with 5 mg amlodipine in elderly hypertensive patients resulted in a 60% increase in amlodipine systemic exposure. Erythromycin co-administration in healthy volunteers did not significantly change amlodipine systemic exposure. However, strong inhibitors of CYP3A4 (e.g., ketoconazole, itraconazole, ritonavir) may increase the plasma concentrations of amlodipine to a greater extent. Monitor for symptoms of hypotension and edema when amlodipine is co-administered with CYP3A4 inhibitors. 7.11 CYP3A4 Inducers No information is available on the quantitative effects of CYP3A4 inducers on amlodipine. Blood pressure should be closely monitored when amlodipine is co-administered with CYP3A4 inducers. 7.12 Drug/Laboratory Test Interactions None known.

OVERDOSAGE

10 Overdosage might be expected to cause excessive peripheral vasodilation with marked hypotension and possibly a reflex tachycardia. In humans, experience with intentional overdosage of NORVASC is limited. Single oral doses of amlodipine maleate equivalent to 40 mg amlodipine/kg and 100 mg amlodipine/kg in mice and rats, respectively, caused deaths. Single oral amlodipine maleate doses equivalent to 4 or more mg amlodipine/kg or higher in dogs (11 or more times the maximum recommended human dose on a mg/m2 basis) caused a marked peripheral vasodilation and hypotension. If massive overdose should occur, initiate active cardiac and respiratory monitoring. Frequent blood pressure measurements are essential. Should hypotension occur, provide cardiovascular support including elevation of the extremities and the judicious administration of fluids. If hypotension remains unresponsive to these conservative measures, consider administration of vasopressors (such as phenylephrine) with attention to circulating volume and urine output. As NORVASC is highly protein bound, hemodialysis is not likely to be of benefit.

DESCRIPTION

11 NORVASC is the besylate salt of amlodipine, a long-acting calcium channel blocker. Amlodipine besylate is chemically described as 3-Ethyl-5-methyl (±)-2-[(2-aminoethoxy)methyl]-4-(2-chlorophenyl)-1,4-dihydro-6-methyl-3,5-pyridinedicarboxylate, monobenzenesulphonate. Its empirical formula is C20H25ClN2O5•C6H6O3S, and its structural formula is: Amlodipine besylate is a white crystalline powder with a molecular weight of 567.1. It is slightly soluble in water and sparingly soluble in ethanol. NORVASC (amlodipine besylate) Tablets are formulated as white tablets equivalent to 2.5, 5, and 10 mg of amlodipine for oral administration. In addition to the active ingredient, amlodipine besylate, each tablet contains the following inactive ingredients: microcrystalline cellulose, dibasic calcium phosphate anhydrous, sodium starch glycolate, and magnesium stearate. Chemical Structure Figure Figure Logo

CLINICAL STUDIES

14 14.1 Effects in Hypertension Adult Patients The antihypertensive efficacy of NORVASC has been demonstrated in a total of 15 double-blind, placebo-controlled, randomized studies involving 800 patients on NORVASC and 538 on placebo. Once daily administration produced statistically significant placebo-corrected reductions in supine and standing blood pressures at 24 hours postdose, averaging about 12/6 mmHg in the standing position and 13/7 mmHg in the supine position in patients with mild to moderate hypertension. Maintenance of the blood pressure effect over the 24-hour dosing interval was observed, with little difference in peak and trough effect. Tolerance was not demonstrated in patients studied for up to 1 year. The 3 parallel, fixed dose, dose response studies showed that the reduction in supine and standing blood pressures was dose-related within the recommended dosing range. Effects on diastolic pressure were similar in young and older patients. The effect on systolic pressure was greater in older patients, perhaps because of greater baseline systolic pressure. Effects were similar in black patients and in white patients. Pediatric Patients Two hundred sixty-eight hypertensive patients aged 6 to 17 years were randomized first to NORVASC 2.5 or 5 mg once daily for 4 weeks and then randomized again to the same dose or to placebo for another 4 weeks. Patients receiving 2.5 mg or 5 mg at the end of 8 weeks had significantly lower systolic blood pressure than those secondarily randomized to placebo. The magnitude of the treatment effect is difficult to interpret, but it is probably less than 5 mmHg systolic on the 5 mg dose and 3.3 mmHg systolic on the 2.5 mg dose. Adverse events were similar to those seen in adults. 14.2 Effects in Chronic Stable Angina The effectiveness of 5–10 mg/day of NORVASC in exercise-induced angina has been evaluated in 8 placebo-controlled, double-blind clinical trials of up to 6 weeks duration involving 1038 patients (684 NORVASC, 354 placebo) with chronic stable angina. In 5 of the 8 studies, significant increases in exercise time (bicycle or treadmill) were seen with the 10 mg dose. Increases in symptom-limited exercise time averaged 12.8% (63 sec) for NORVASC 10 mg, and averaged 7.9% (38 sec) for NORVASC 5 mg. NORVASC 10 mg also increased time to 1 mm ST segment deviation in several studies and decreased angina attack rate. The sustained efficacy of NORVASC in angina patients has been demonstrated over long-term dosing. In patients with angina, there were no clinically significant reductions in blood pressures (4/1 mmHg) or changes in heart rate (+0.3 bpm). 14.3 Effects in Vasospastic Angina In a double-blind, placebo-controlled clinical trial of 4 weeks duration in 50 patients, NORVASC therapy decreased attacks by approximately 4/week compared with a placebo decrease of approximately 1/week (p<0.01). Two of 23 NORVASC and 7 of 27 placebo patients discontinued from the study due to lack of clinical improvement. 14.4 Effects in Documented Coronary Artery Disease In PREVENT, 825 patients with angiographically documented coronary artery disease were randomized to NORVASC (5–10 mg once daily) or placebo and followed for 3 years. Although the study did not show significance on the primary objective of change in coronary luminal diameter as assessed by quantitative coronary angiography, the data suggested a favorable outcome with respect to fewer hospitalizations for angina and revascularization procedures in patients with CAD. CAMELOT enrolled 1318 patients with CAD recently documented by angiography, without left main coronary disease and without heart failure or an ejection fraction <40%. Patients (76% males, 89% Caucasian, 93% enrolled at US sites, 89% with a history of angina, 52% without PCI, 4% with PCI and no stent, and 44% with a stent) were randomized to double-blind treatment with either NORVASC (5–10 mg once daily) or placebo in addition to standard care that included aspirin (89%), statins (83%), beta-blockers (74%), nitroglycerin (50%), anti-coagulants (40%), and diuretics (32%), but excluded other calcium channel blockers. The mean duration of follow-up was 19 months. The primary endpoint was the time to first occurrence of one of the following events: hospitalization for angina pectoris, coronary revascularization, myocardial infarction, cardiovascular death, resuscitated cardiac arrest, hospitalization for heart failure, stroke/TIA, or peripheral vascular disease. A total of 110 (16.6%) and 151 (23.1%) first events occurred in the NORVASC and placebo groups, respectively, for a hazard ratio of 0.691 (95% CI: 0.540–0.884, p = 0.003). The primary endpoint is summarized in Figure 1 below. The outcome of this study was largely derived from the prevention of hospitalizations for angina and the prevention of revascularization procedures (see Table 1). Effects in various subgroups are shown in Figure 2. In an angiographic substudy (n=274) conducted within CAMELOT, there was no significant difference between amlodipine and placebo on the change of atheroma volume in the coronary artery as assessed by intravascular ultrasound. Figure 1 – Kaplan-Meier Analysis of Composite Clinical Outcomes for NORVASC versus Placebo Figure 2 – Effects on Primary Endpoint of NORVASC versus Placebo across Sub-Groups Table 1 below summarizes the significant composite endpoint and clinical outcomes from the composites of the primary endpoint. The other components of the primary endpoint including cardiovascular death, resuscitated cardiac arrest, myocardial infarction, hospitalization for heart failure, stroke/TIA, or peripheral vascular disease did not demonstrate a significant difference between NORVASC and placebo. Table 1. Incidence of Significant Clinical Outcomes for CAMELOT Clinical Outcomes N (%) NORVASC (N=663) Placebo (N=655) Risk Reduction (p-value) Composite CV Endpoint 110 (16.6) 151 (23.1) 31% (0.003) Hospitalization for AnginaTotal patients with these events 51 (7.7) 84 (12.8) 42% (0.002) Coronary Revascularization 78 (11.8) 103 (15.7) 27% (0.033) 14.5 Studies in Patients with Heart Failure NORVASC has been compared to placebo in four 8–12 week studies of patients with NYHA Class II/III heart failure, involving a total of 697 patients. In these studies, there was no evidence of worsened heart failure based on measures of exercise tolerance, NYHA classification, symptoms, or left ventricular ejection fraction. In a long-term (follow-up at least 6 months, mean 13.8 months) placebo-controlled mortality/morbidity study of NORVASC 5–10 mg in 1153 patients with NYHA Classes III (n=931) or IV (n=222) heart failure on stable doses of diuretics, digoxin, and ACE inhibitors, NORVASC had no effect on the primary endpoint of the study which was the combined endpoint of all-cause mortality and cardiac morbidity (as defined by life-threatening arrhythmia, acute myocardial infarction, or hospitalization for worsened heart failure), or on NYHA classification, or symptoms of heart failure. Total combined all-cause mortality and cardiac morbidity events were 222/571 (39%) for patients on NORVASC and 246/583 (42%) for patients on placebo; the cardiac morbid events represented about 25% of the endpoints in the study. Another study (PRAISE-2) randomized patients with NYHA Class III (80%) or IV (20%) heart failure without clinical symptoms or objective evidence of underlying ischemic disease, on stable doses of ACE inhibitors (99%), digitalis (99%), and diuretics (99%), to placebo (n=827) or NORVASC (n=827) and followed them for a mean of 33 months. There was no statistically significant difference between NORVASC and placebo in the primary endpoint of all-cause mortality (95% confidence limits from 8% reduction to 29% increase on NORVASC). With NORVASC there were more reports of pulmonary edema.

HOW SUPPLIED

16 /STORAGE AND HANDLING 16.1 2.5 mg Tablets NORVASC – 2.5 mg Tablets (amlodipine besylate equivalent to 2.5 mg of amlodipine per tablet) are supplied as white, diamond, flat-faced, beveled edged engraved with “NORVASC” on one side and “2.5” on the other side and supplied as follows: NDC 0069-1520-68 Bottle of 90 16.2 5 mg Tablets NORVASC – 5 mg Tablets (amlodipine besylate equivalent to 5 mg of amlodipine per tablet) are white, elongated octagon, flat-faced, beveled edged engraved with both “NORVASC” and “5” on one side and plain on the other side and supplied as follows: NDC 0069-1530-68 Bottle of 90 NDC 0069-1530-41 Unit Dose package of 100 NDC 0069-1530-72 Bottle of 300 16.3 10 mg Tablets NORVASC – 10 mg Tablets (amlodipine besylate equivalent to 10 mg of amlodipine per tablet) are white, round, flat-faced, beveled edged engraved with both “NORVASC” and “10” on one side and plain on the other side and supplied as follows: NDC 0069-1540-68 Bottle of 90 NDC 0069-1540-41 Unit Dose package of 100 16.4 Storage Store bottles at controlled room temperature, 59° to 86°F (15° to 30°C) and dispense in tight, light-resistant containers (USP).

GERIATRIC USE

8.5 Geriatric Use Clinical studies of NORVASC did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. Elderly patients have decreased clearance of amlodipine with a resulting increase of AUC of approximately 40–60%, and a lower initial dose may be required [see Dosage and Administration (2.1)].

DOSAGE FORMS AND STRENGTHS

3 2.5, 5, and 10 mg Tablets 2.5 mg, 5 mg, and 10 mg Tablets (3)

MECHANISM OF ACTION

12.1 Mechanism of Action Amlodipine is a dihydropyridine calcium antagonist (calcium ion antagonist or slow-channel blocker) that inhibits the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle. Experimental data suggest that amlodipine binds to both dihydropyridine and nondihydropyridine binding sites. The contractile processes of cardiac muscle and vascular smooth muscle are dependent upon the movement of extracellular calcium ions into these cells through specific ion channels. Amlodipine inhibits calcium ion influx across cell membranes selectively, with a greater effect on vascular smooth muscle cells than on cardiac muscle cells. Negative inotropic effects can be detected in vitro but such effects have not been seen in intact animals at therapeutic doses. Serum calcium concentration is not affected by amlodipine. Within the physiologic pH range, amlodipine is an ionized compound (pKa=8.6), and its kinetic interaction with the calcium channel receptor is characterized by a gradual rate of association and dissociation with the receptor binding site, resulting in a gradual onset of effect. Amlodipine is a peripheral arterial vasodilator that acts directly on vascular smooth muscle to cause a reduction in peripheral vascular resistance and reduction in blood pressure. The precise mechanisms by which amlodipine relieves angina have not been fully delineated, but are thought to include the following: Exertional Angina: In patients with exertional angina, NORVASC reduces the total peripheral resistance (afterload) against which the heart works and reduces the rate pressure product, and thus myocardial oxygen demand, at any given level of exercise. Vasospastic Angina: NORVASC has been demonstrated to block constriction and restore blood flow in coronary arteries and arterioles in response to calcium, potassium epinephrine, serotonin, and thromboxane A2 analog in experimental animal models and in human coronary vessels in vitro. This inhibition of coronary spasm is responsible for the effectiveness of NORVASC in vasospastic (Prinzmetal’s or variant) angina.

INDICATIONS AND USAGE

1 NORVASC is a calcium channel blocker and may be used alone or in combination with other antihypertensive and antianginal agents for the treatment of: Hypertension (1.1) Coronary Artery Disease (1.2) Chronic Stable Angina Vasospastic Angina (Prinzmetal’s or Variant Angina) Angiographically Documented Coronary Artery Disease in patients without heart failure or an ejection fraction < 40% 1.1 Hypertension NORVASC® is indicated for the treatment of hypertension. It may be used alone or in combination with other antihypertensive agents. 1.2 Coronary Artery Disease (CAD) Chronic Stable Angina NORVASC is indicated for the symptomatic treatment of chronic stable angina. NORVASC may be used alone or in combination with other antianginal agents. Vasospastic Angina (Prinzmetal's or Variant Angina) NORVASC is indicated for the treatment of confirmed or suspected vasospastic angina. NORVASC may be used as monotherapy or in combination with other antianginal agents. Angiographically Documented CAD In patients with recently documented CAD by angiography and without heart failure or an ejection fraction <40%, NORVASC is indicated to reduce the risk of hospitalization due to angina and to reduce the risk of a coronary revascularization procedure.

PEDIATRIC USE

8.4 Pediatric Use Effect of NORVASC on blood pressure in patients less than 6 years of age is not known.

PREGNANCY

8.1 Pregnancy Pregnancy Category C There are no adequate and well-controlled studies in pregnant women. Amlodipine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. No evidence of teratogenicity or other embryo/fetal toxicity was found when pregnant rats and rabbits were treated orally with amlodipine maleate at doses up to 10 mg amlodipine/kg/day (respectively, 8 timesBased on patient weight of 50 kg. and 23 times the maximum recommended human dose of 10 mg on a mg/m2 basis) during their respective periods of major organogenesis. However, litter size was significantly decreased (by about 50%) and the number of intrauterine deaths was significantly increased (about 5-fold) in rats receiving amlodipine maleate at a dose equivalent to 10 mg amlodipine/kg/day for 14 days before mating and throughout mating and gestation. Amlodipine maleate has been shown to prolong both the gestation period and the duration of labor in rats at this dose.

NUSRING MOTHERS

8.3 Nursing Mothers It is not known whether amlodipine is excreted in human milk. In the absence of this information, it is recommended that nursing be discontinued while NORVASC is administered.

WARNING AND CAUTIONS

5 WARNINGS AND PRECAUTIONS Symptomatic hypotension is possible, particularly in patients with severe aortic stenosis. However, because of the gradual onset of action, acute hypotension is unlikely. (5.1) Worsening angina and acute myocardial infarction can develop after starting or increasing the dose of NORVASC, particularly in patients with severe obstructive coronary artery disease. (5.2) Titrate slowly when administering calcium channel blockers to patients with severe hepatic impairment. (5.4) 5.1 Hypotension Symptomatic hypotension is possible, particularly in patients with severe aortic stenosis. Because of the gradual onset of action, acute hypotension is unlikely. 5.2 Increased Angina or Myocardial Infarction Worsening angina and acute myocardial infarction can develop after starting or increasing the dose of NORVASC, particularly in patients with severe obstructive coronary artery disease. 5.3 Beta-Blocker Withdrawal NORVASC is not a beta-blocker and therefore gives no protection against the dangers of abrupt beta-blocker withdrawal; any such withdrawal should be by gradual reduction of the dose of beta-blocker. 5.4 Patients with Hepatic Failure Because NORVASC is extensively metabolized by the liver and the plasma elimination half-life (t 1/2) is 56 hours in patients with impaired hepatic function, titrate slowly when administering NORVASC to patients with severe hepatic impairment.

DOSAGE AND ADMINISTRATION

2 Adult recommended starting dose: 5 mg once daily with maximum dose 10 mg once daily. (2.1) Small, fragile, or elderly patients, or patients with hepatic insufficiency may be started on 2.5 mg once daily. (2.1) Pediatric starting dose: 2.5 mg to 5 mg once daily. (2.2) Important Limitation: Doses in excess of 5 mg daily have not been studied in pediatric patients. (2.2) 2.1 Adults The usual initial antihypertensive oral dose of NORVASC is 5 mg once daily with a maximum dose of 10 mg once daily. Small, fragile, or elderly patients, or patients with hepatic insufficiency may be started on 2.5 mg once daily and this dose may be used when adding NORVASC to other antihypertensive therapy. Adjust dosage according to each patient’s need. In general, titration should proceed over 7 to 14 days so that the physician can fully assess the patient’s response to each dose level. Titration may proceed more rapidly, however, if clinically warranted, provided the patient is assessed frequently. The recommended dose for chronic stable or vasospastic angina is 5–10 mg, with the lower dose suggested in the elderly and in patients with hepatic insufficiency. Most patients will require 10 mg for adequate effect [see Adverse Reactions (6)]. The recommended dose range for patients with coronary artery disease is 5–10 mg once daily. In clinical studies, the majority of patients required 10 mg [see Clinical Studies (14.4)]. 2.2 Children The effective antihypertensive oral dose in pediatric patients ages 6–17 years is 2.5 mg to 5 mg once daily. Doses in excess of 5 mg daily have not been studied in pediatric patients [see Clinical Pharmacology (12.4), Clinical Studies (14.1)].