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Geriatric Use — Plasma concentrations of felodipine, after a single dose and at steady state, increase with age. Mean clearance of felodipine in elderly hypertensives (mean age 74) was only 45% of that of young volunteers (mean age 26). At steady state mean AUC for young patients was 39% of that for the elderly. Data for intermediate age ranges suggest that the AUCs fall between the extremes of the young and the elderly.
Hepatic Dysfunction — In patients with hepatic disease, the clearance of felodipine was reduced to about 60% of that seen in normal young volunteers.
Renal impairment does not alter the plasma concentration profile of felodipine; although higher concentrations of the metabolites are present in the plasma due to decreased urinary excretion, these are inactive.
Animal studies have demonstrated that felodipine crosses the blood-brain barrier and the placenta.
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 2–3 weeks of the initiation of treatment.
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 Cmax, 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 Cmax, 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 Cmax, 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 Cmax, 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 Cmax 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.
Pregnancy Category C.
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.
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; therefore, patients should have their blood pressure monitored closely during dosage adjustment of felodipine extended-release tablets (see CLINICAL PHARMACOLOGY).
Distributed by: Sun Pharmaceutical Industries, Inc.
Cranbury, NJ 08512
Rev 07, November 2014