Adults

Hypertension: Initial dose 5 mg once daily, adjusted according to response, usually at 2-week intervals. Usual maintenance dose is 5-10 mg once daily, max 20 mg once daily. Angina: Initial dose 5 mg once daily, maintenance dose typically 10 mg once daily.

Elderly

A lower initial dose (e.g., 2.5 mg or 5 mg once daily) should be considered, with careful titration.

Renal_impairment

No dose adjustment is generally required in patients with renal impairment.

Onset

Antihypertensive effect onset within 2.5 to 5 hours.

Excretion

Approximately 70% excreted in urine and 10% in feces, primarily as inactive metabolites.

Half life

Terminal elimination half-life is 10-16 hours.

Absorption

Rapidly and extensively absorbed from the gastrointestinal tract, but undergoes extensive first-pass metabolism. Absolute bioavailability is approximately 15%.

Metabolism

Extensively metabolized in the liver, primarily by CYP3A4. All identified metabolites are inactive.

Beta-blockers and other Antihypertensives

May have additive hypotensive effects.

CYP3A4 Inhibitors (e.g., ketoconazole, erythromycin, cimetidine)

Can significantly increase plasma concentrations of felodipine, leading to increased hypotensive effects and peripheral edema.

CYP3A4 Inducers (e.g., rifampicin, phenytoin, carbamazepine, phenobarbital)

Can significantly decrease plasma concentrations of felodipine, leading to reduced therapeutic effects.