FELODIPINE: 1,476 Adverse Event Reports & Safety Profile

DESCRIPTION Felodipine extended-release tablets USP are a calcium antagonist (calcium channel blocker). Felodipine is a dihydropyridine derivative that is chemically described as ± ethyl methyl 4-(2,3-dichlorophenyl)-1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylate. Its molecular formula is C 18 H 19 Cl 2 NO 4 and its structural formula is: Felodipine USP is a slightly yellowish, crystalline powder with a molecular weight of 384.26. It is insoluble in water and is freely soluble in dichloromethane and ethanol. Felodipine is a racemic mixture. Felodipine extended-release tablets provide extended-release of felodipine. They are available as tablets containing 2.5 mg, 5 mg, or 10 mg of felodipine for oral administration. In addition to the active ingredient felodipine, the felodipine extended-release tablets 2.5 mg, 5 mg and 10 mg contain the following inactive ingredients: hydroxypropyl cellulose, hypromellose, kaolin, lactose monohydrate, microcrystalline cellulose, polyoxyl 40 hydrogenated castor oil, sodium stearyl fumarate, Opadry Green 20B51525 (2.5 mg), Opadry Pink 20B84706 (5 mg) and Opadry Red 20B55372 (10 mg).

Opadry Green

20B51525 consists of hypromellose, hydroxypropyl cellulose, macrogol, titanium dioxide, D&C Yellow No. 10 Aluminium Lake, FD&C Blue No. 2 Aluminium Lake and ferric oxide yellow.

Opadry Pink

20B84706 consists of hypromellose, hydroxypropyl cellulose, macrogol, titanium dioxide, ferric oxide red and ferric oxide yellow.

Opadry Red

20B55372 consists of hypromellose, hydroxypropyl cellulose, macrogol, titanium dioxide, ferric oxide red and ferric oxide yellow. structure

INDICATIONS AND USAGE Felodipine extended-release tablets, USP are indicated for the treatment of hypertension, to lower blood pressure. Lowering blood pressure lowers the risk of fatal and non-fatal cardiovascular events, primarily strokes and myocardial infarctions. These benefits have been seen in controlled trials of antihypertensive drugs from a wide variety of pharmacologic classes including felodipine. Control of high blood pressure should be part of comprehensive cardiovascular risk management, including, as appropriate, lipid control, diabetes management, antithrombotic therapy, smoking cessation, exercise, and limited sodium intake. Many patients will require more than 1 drug to achieve blood pressure goals. For specific advice on goals and management, see published guidelines, such as those of the National High Blood Pressure Education Program’s Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC). Numerous antihypertensive drugs, from a variety of pharmacologic classes and with different mechanisms of action, have been shown in randomized controlled trials to reduce cardiovascular morbidity and mortality, and it can be concluded that it is blood pressure reduction, and not some other pharmacologic property of the drugs, that is largely responsible for those benefits. The largest and most consistent cardiovascular outcome benefit has been a reduction in the risk of stroke, but reductions in myocardial infarction and cardiovascular mortality also have been seen regularly. Elevated systolic or diastolic pressure causes increased cardiovascular risk, and the absolute risk increase per mmHg is greater at higher blood pressures, so that even modest reductions of severe hypertension can provide substantial benefit. Relative risk reduction from blood pressure reduction is similar across populations with varying absolute risk, so the absolute benefit is greater in patients who are at higher risk independent of their hypertension (for example, patients with diabetes or hyperlipidemia), and such patients would be expected to benefit from more aggressive treatment to a lower blood pressure goal. Some antihypertensive drugs have smaller blood pressure effects (as monotherapy) in black patients, and many antihypertensive drugs have additional approved indications and effects (e.g., on angina, heart failure, or diabetic kidney disease). These considerations may guide selection of therapy. Felodipine extended-release tablets, USP may be administered with other antihypertensive agents.

DOSAGE AND ADMINISTRATION The recommended starting dose is 5 mg once a day. Depending on the patient's response, the dosage can be decreased to 2.5 mg or increased to 10 mg once a day. These adjustments should occur generally at intervals of not less than 2 weeks. The recommended dosage range is 2.5 to 10 mg once daily. In clinical trials, doses above 10 mg daily showed an increased blood pressure response but a large increase in the rate of peripheral edema and other vasodilatory adverse events (see ADVERSE REACTIONS ). Modification of the recommended dosage is usually not required in patients with renal impairment. Felodipine extended-release tablets, USP should regularly be taken either without food or with a light meal (see CLINICAL PHARMACOLOGY, Pharmacokinetics and Metabolism ). Felodipine extended-release tablets, USP should be swallowed whole and not crushed or chewed.

Geriatric Use

Patients over 65 years of age are likely to develop higher plasma concentrations of felodipine (see CLINICAL PHARMACOLOGY ). In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range (2.5 mg daily). Elderly patients should have their blood pressure closely monitored during any dosage adjustment. Patients with Impaired Liver Function Patients with impaired liver function may have elevated plasma concentrations of felodipine and may respond to lower doses of felodipine extended-release tablets, USP; therefore, patients should have their blood pressure monitored closely during dosage adjustment of felodipine extended-release tablets, USP (see CLINICAL PHARMACOLOGY ).

CONTRAINDICATIONS Felodipine extended-release tablets, USP are contraindicated in patients who are hypersensitive to this product.

ADVERSE REACTIONS In controlled studies in the United States and overseas, approximately 3000 patients were treated with felodipine as either the extended-release or the immediate-release formulation. The most common clinical adverse events reported with felodipine extended-release administered as monotherapy at the recommended dosage range of 2.5 mg to 10 mg once a day were peripheral edema and headache. Peripheral edema was generally mild, but it was age and dose related and resulted in discontinuation of therapy in about 3% of the enrolled patients. Discontinuation of therapy due to any clinical adverse event occurred in about 6% of the patients receiving felodipine extended-release tablets, principally for peripheral edema, headache, or flushing. Adverse events that occurred with an incidence of 1.5% or greater at any of the recommended doses of 2.5 mg to 10 mg once a day (felodipine extended-release tablets, N = 861; Placebo, N = 334), without regard to causality, are compared to placebo and are listed by dose in the table below. These events are reported from controlled clinical trials with patients who were randomized to a fixed dose of felodipine extended-release tablets or titrated from an initial dose of 2.5 mg or 5 mg once a day. A dose of 20 mg once a day has been evaluated in some clinical studies. Although the antihypertensive effect of felodipine extended-release tablets is increased at 20 mg once a day, there is a disproportionate increase in adverse events, especially those associated with vasodilatory effects (see DOSAGE AND ADMINISTRATION ). Percent of Patients with Adverse Events in Controlled Trials* of Felodipine Extended-Release Tablets (N = 861) as Monotherapy without Regard to Causality (Incidence of discontinuations shown in parentheses)

Body System Adverse Events

Placebo N=334 2.5 mg N=255 5 mg N=581 10 mg N= 408 Body as a whole Peripheral Edema 3.3 (0.0) 2.0 (0.0) 8.8 (2.2) 17.4 (2.5)

Asthenia

3.3 (0.0) 3.9 (0.0) 3.3 (0.0) 2.2 (0.0)

Warm Sensation

0.0 (0.0) 0.0 (0.0) 0.9 (0.2) 1.5 (0.0)

Cardiovascular Palpitation

2.4 (0.0) 0.4 (0.0) 1.4 (0.3) 2.5 (0.5)

Digestive Nausea

1.5 (0.9) 1.2 (0.0) 1.7 (0.3) 1.0 (0.7)

Dyspepsia

1.2 (0.0) 3.9 (0.0) 0.7 (0.0) 0.5 (0.0)

Constipation

0.9 (0.0) 1.2 (0.0) 0.3 (0.0) 1.5 (0.2)

Nervous Headache

10.2 (0.9) 10.6 (0.4) 11.0 (1.7) 14.7 (2.0)

Dizziness

2.7 (0.3) 2.7 (0.0) 3.6 (0.5) 3.7 (0.5)

Paresthesia

1.5 (0.3) 1.6 (0.0) 1.2 (0.0) 1.2 (0.2)

Respiratory Upper Respiratory Infection

1.8 (0.0) 3.9 (0.0) 1.9 (0.0) 0.7 (0.0)

Cough

0.3 (0.0) 0.8 (0.0) 1.2 (0.0) 1.7 (0.0)

Rhinorrhea

0.0 (0.0) 1.6 (0.0) 0.2 (0.0) 0.2 (0.0)

Sneezing

0.0 (0.0) 1.6 (0.0) 0.0 (0.0) 0.0 (0.0)

Skin Rash

0.9 (0.0) 2.0 (0.0) 0.2 (0.0) 0.2 (0.0)

Flushing

0.9 (0.3) 3.9 (0.0) 5.3 (0.7) 6.9 (1.2) *Patients in titration studies may have been exposed to more than one dose level of felodipine extended-release tablets. Adverse events that occurred in 0.5 up to 1.5% of patients who received felodipine extended-release tablets in all controlled clinical trials at the recommended dosage range of 2.5 mg to 10 mg once a day, and serious adverse events that occurred at a lower rate, or events reported during marketing experience (those lower rate events are in italics) are listed below. These events are listed in order of decreasing severity within each category, and the relationship of these events to administration of felodipine extended-release tablets are uncertain: Body as a Whole : Chest pain, facial edema, flu-like illness Cardiovascular : Myocardial infarction, hypotension, syncope, angina pectoris , arrhythmia , tachycardia, premature beats Digestive: Abdominal pain, diarrhea, vomiting, dry mouth, flatulence, acid regurgitation Endocrine: Gynecomastia Hematologic: Anemia Metabolic : ALT (SGPT) increased Musculoskeletal: Arthralgia, back pain, leg pain, foot pain, muscle cramps, myalgia, arm pain, knee pain, hip pain Nervous/Psychiatric : Insomnia, depression, anxiety disorders, irritability, nervousness, somnolence, decreased libido Respiratory : Dyspnea, pharyngitis, bronchitis, influenza, sinusitis, epistaxis, respiratory infection Skin : Angioedema, contusion, erythema, urticaria , leukocytoclastic vasculitis Special Senses : Visual disturbances Urogenital : Impotence, urinary frequency, urinary urgency, dysuria, polyuria.

Gingival

Hyperplasia : Gingival hyperplasia, usually mild, occurred in < 0.5% of patients in controlled studies. This condition may be avoided or may regress with improved dental hygiene. (See PRECAUTIONS, Information for Patients .)

Clinical Laboratory Test Findings Serum

Electrolytes - No significant effects on serum electrolytes were observed during short- and long-term therapy (see CLINICAL PHARMACOLOGY:Renal/Endocrine Effects ).

Serum

Glucose - No significant effects on fasting serum glucose were observed in patients treated with felodipine extended-release tablets in the U.S. controlled study.

Liver

Enzymes - 1 of 2 episodes of elevated serum transaminases decreased once drug was discontinued in clinical studies; no follow-up was available for the other patient. To report SUSPECTED ADVERSE REACTIONS, contact Avet Pharmaceuticals Inc. at 1-866-901-DRUG (3784) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

PRECAUTIONS General Hypotension Felodipine, like other calcium antagonists, may occasionally precipitate significant hypotension and, rarely, syncope. It may lead to reflex tachycardia which in susceptible individuals may precipitate angina pectoris. (See ADVERSE REACTIONS .)

Heart Failure

Although acute hemodynamic studies in a small number of patients with NYHA Class II or III heart failure treated with felodipine have not demonstrated negative inotropic effects, safety in patients with heart failure has not been established. Caution, therefore, should be exercised when using felodipine extended-release tablets in patients with heart failure or compromised ventricular function, particularly in combination with a beta blocker. Patients with Impaired Liver Function Patients with impaired liver function may have elevated plasma concentrations of felodipine and may respond to lower doses of felodipine extended-release tablets; therefore, a starting dose of 2.5 mg once a day is recommended. These patients should have their blood pressure monitored closely during dosage adjustment of felodipine extended-release tablets. (See CLINICAL PHARMACOLOGY and DOSAGE AND ADMINISTRATION .)

Peripheral Edema

Peripheral edema, generally mild and not associated with generalized fluid retention, was the most common adverse event in the clinical trials. The incidence of peripheral edema was both dose and age dependent. Frequency of peripheral edema ranged from about 10% in patients under 50 years of age taking 5 mg daily to about 30% in those over 60 years of age taking 20 mg daily. This adverse effect generally occurs within 2 to 3 weeks of the initiation of treatment. Information for Patients Patients should be instructed to take felodipine extended-release tablets whole and not to crush or chew the tablets. They should be told that mild gingival hyperplasia (gum swelling) has been reported. Good dental hygiene decreases its incidence and severity. NOTE: As with many other drugs, certain advice to patients being treated with felodipine extended-release tablets is warranted. This information is intended to aid in the safe and effective use of this medication. It is not a disclosure of all possible adverse or intended effects.

Drug

Interactions CYP3A4 Inhibitors Felodipine is metabolized by CYP3A4. Co-administration of CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, erythromycin, grapefruit juice, cimetidine) with felodipine may lead to several-fold increases in the plasma levels of felodipine, either due to an increase in bioavailability or due to a decrease in metabolism. These increases in concentration may lead to increased effects, (lower blood pressure and increased heart rate). These effects have been observed with co-administration of itraconazole (a potent CYP3A4 inhibitor). Caution should be used when CYP3A4 inhibitors are co-administered with felodipine. A conservative approach to dosing felodipine should be taken. The following specific interactions have been reported: Itraconazole Co-administration of another extended-release formulation of felodipine with itraconazole resulted in approximately 8-fold increase in the AUC, more than 6-fold increase in the C max , and 2-fold prolongation in the half-life of felodipine. Erythromycin Co-administration of felodipine extended-release tablets with erythromycin resulted in approximately 2.5-fold increase in the AUC and C max , and about 2-fold prolongation in the half-life of felodipine.

Grapefruit

Juice Co-administration of felodipine with grapefruit juice resulted in more than 2-fold increase in the AUC and C max , but no prolongation in the half-life of felodipine. Cimetidine Co-administration of felodipine with cimetidine (a non-specific CYP-450 inhibitor) resulted in an increase of approximately 50% in the AUC and the C max , of felodipine. Beta-Blocking Agents A pharmacokinetic study of felodipine in conjunction with metoprolol demonstrated no significant effects on the pharmacokinetics of felodipine. The AUC and C max of metoprolol, however, were increased approximately 31 and 38%, respectively. In controlled clinical trials, however, beta blockers including metoprolol were concurrently administered with felodipine and were well tolerated.

Digoxin

When given concomitantly with felodipine extended-release tablets the pharmacokinetics of digoxin in patients with heart failure were not significantly altered. Anticonvulsants In a pharmacokinetic study, maximum plasma concentrations of felodipine were considerably lower in epileptic patients on long-term anticonvulsant therapy (e.g., phenytoin, carbamazepine, or phenobarbital) than in healthy volunteers. In such patients, the mean area under the felodipine plasma concentration-time curve was also reduced to approximately 6% of that observed in healthy volunteers. Since a clinically significant interaction may be anticipated, alternative antihypertensive therapy should be considered in these patients.

Tacrolimus

Felodipine may increase the blood concentration of tacrolimus. When given concomitantly with felodipine, the tacrolimus blood concentration should be followed and the tacrolimus dose may need to be adjusted.

Other Concomitant

Therapy In healthy subjects there were no clinically significant interactions when felodipine was given concomitantly with indomethacin or spironolactone. Interaction with Food See CLINICAL PHARMACOLOGY: Pharmacokinetics and Metabolism . Carcinogenesis, Mutagenesis, Impairment of Fertility In a 2-year carcinogenicity study in rats fed felodipine at doses of 7.7, 23.1 or 69.3 mg/kg/day (up to 61 times ** the maximum recommended human dose on a mg/m 2 basis), a dose-related increase in the incidence of benign interstitial cell tumors of the testes (Leydig cell tumors) was observed in treated male rats. These tumors were not observed in a similar study in mice at doses up to 138.6 mg/kg/day (61 times ** the maximum recommended human dose on a mg/m 2 basis). Felodipine, at the doses employed in the 2-year rat study, has been shown to lower testicular testosterone and to produce a corresponding increase in serum luteinizing hormone in rats.

The

Leydig cell tumor development is possibly secondary to these hormonal effects which have not been observed in man. In this same rat study a dose-related increase in the incidence of focal squamous cell hyperplasia compared to control was observed in the esophageal groove of male and female rats in all dose groups. No other drug-related esophageal or gastric pathology was observed in the rats or with chronic administration in mice and dogs. The latter species, like man, has no anatomical structure comparable to the esophageal groove. Felodipine was not carcinogenic when fed to mice at doses up to 138.6 mg/kg/day (61 times ** the maximum recommended human dose on a mg/m 2 basis) for periods of up to 80 weeks in males and 99 weeks in females. Felodipine did not display any mutagenic activity in vitro in the Ames microbial mutagenicity test or in the mouse lymphoma forward mutation assay. No clastogenic potential was seen in vivo in the mouse micronucleus test at oral doses up to 2500 mg/kg (1100 times ** the maximum recommended human dose on a mg/m 2 basis) or in vitro in a human lymphocyte chromosome aberration assay. A fertility study in which male and female rats were administered doses of 3.8, 9.6 or 26.9 mg/kg/day (up to 24 times ** the maximum recommended human dose on a mg/m 2 basis) showed no significant effect of felodipine on reproductive performance. ____________________________ ** Based on patient weight of 50 kg Pregnancy Pregnancy Category C Teratogenic Effects Studies in pregnant rabbits administered doses of 0.46, 1.2, 2.3, and 4.6 mg/kg/day (from 0.8 to 8 times ** the maximum recommended human dose on a mg/m 2 basis) showed digital anomalies consisting of reduction in size and degree of ossification of the terminal phalanges in the fetuses. The frequency and severity of the changes appeared dose related and were noted even at the lowest dose. These changes have been shown to occur with other members of the dihydropyridine class and are possibly a result of compromised uterine blood flow. Similar fetal anomalies were not observed in rats given felodipine. In a teratology study in cynomolgus monkeys, no reduction in the size of the terminal phalanges was observed, but an abnormal position of the distal phalanges was noted in about 40% of the fetuses.

Nonteratogenic

Effects A prolongation of parturition with difficult labor and an increased frequency of fetal and early postnatal deaths were observed in rats administered doses of 9.6 mg/kg/day (8 times ** the maximum human dose on a mg/m 2 basis) and above. Significant enlargement of the mammary glands, in excess of the normal enlargement for pregnant rabbits, was found with doses greater than or equal to 1.2 mg/kg/day (2.1 times the maximum human dose on a mg/m 2 basis). This effect occurred only in pregnant rabbits and regressed during lactation. Similar changes in the mammary glands were not observed in rats or monkeys. There are no adequate and well-controlled studies in pregnant women. If felodipine is used during pregnancy, or if the patient becomes pregnant while taking this drug, she should be apprised of the potential hazard to the fetus, possible digital anomalies of the infant, and the potential effects of felodipine on labor and delivery and on the mammary glands of pregnant females. ____________________________ ** Based on patient weight of 50 kg Nursing Mothers It is not known whether this drug is secreted in human milk and because of the potential for serious adverse reactions from felodipine in the infant, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Pediatric Use

Safety and effectiveness in pediatric patients have not been established.

Geriatric Use

Clinical studies of felodipine 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. Pharmacokinetics, however, indicate that the availability of felodipine is increased in older patients (see CLINICAL PHARMACOLOGY: Geriatric Use ). 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.

Drug Interactions CYP3A4 Inhibitors Felodipine is metabolized by CYP3A4. Coadministration of CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, erythromycin, grapefruit juice, cimetidine) with felodipine may lead to several-fold increases in the plasma levels of felodipine, either due to an increase in bioavailability or due to a decrease in metabolism. These increases in concentration may lead to increased effects (lower blood pressure and increased heart rate). These effects have been observed with coadministration of itraconazole (a potent CYP3A4 inhibitor). Caution should be used when CYP3A4 inhibitors are coadministered with felodipine. A conservative approach to dosing felodipine should be taken. The following specific interactions have been reported: Itraconazole Coadministration of another extended-release formulation of felodipine with itraconazole resulted in approximately 8-fold increase in the AUC, more than 6-fold increase in the C max , and 2-fold prolongation in the half-life of felodipine.

Erythromycin

Coadministration of felodipine extended-release tablets with erythromycin resulted in approximately 2.5-fold increase in the AUC and C max , and about 2-fold prolongation in the half-life of felodipine.

Grapefruit Juice

Coadministration of felodipine extended-release tablets with grapefruit juice resulted in more than 2-fold increase in the AUC and Cmax, but no prolongation in the half-life of felodipine.

Cimetidine

Coadministration of felodipine with cimetidine (a non-specific CYP-450 inhibitor) resulted in an increase of approximately 50% in the AUC and the C max , of felodipine. Beta-Blocking Agents A pharmacokinetic study of felodipine in conjunction with metoprolol demonstrated no significant effects on the pharmacokinetics of felodipine. The AUC and C max of metoprolol, however, were increased approximately 31 and 38%, respectively. In controlled clinical trials, however, beta-blockers including metoprolol were concurrently administered with felodipine and were well tolerated.

Digoxin

When given concomitantly with felodipine extended-release tablets the pharmacokinetics of digoxin in patients with heart failure were not significantly altered. Anticonvulsants In a pharmacokinetic study, maximum plasma concentrations of felodipine were considerably lower in epileptic patients on long-term anticonvulsant therapy (e.g. phenytoin, carbamazepine, or phenobarbital) than in healthy volunteers. In such patients, the mean area under the felodipine plasma concentration-time curve was also reduced to approximately 6% of that observed in healthy volunteers. Since a clinically significant interaction may be anticipated, alternative antihypertensive therapy should be considered in these patients.

Tacrolimus

Felodipine may increase the blood concentration of tacrolimus. When given concomitantly with felodipine, the tacrolimus blood concentration should be followed and the tacrolimus dose may need to be adjusted.

Other Concomitant

Therapy In healthy subjects there were no clinically significant interactions when felodipine was given concomitantly with indomethacin or spironolactone. Interaction with Food See CLINICAL PHARMACOLOGY: Pharmacokinetics and Metabolism .