Classifications: calcium channel blocker; antihypertensive; Therapeutic: antihypertensive
Pregnancy Category: C
2.5 mg, 5 mg, 10 mg sustained release tablets
Calcium antagonist with high vascular selectivity that reduces systolic, diastolic, and mean arterial pressure at rest and
during exercise. Felodipine inhibits influx of extracellular calcium across myocardial and vascular smooth muscle cell membranes.
Resultant decrease in intracellular calcium inhibits contractility of smooth muscle, resulting in dilation of coronary and
BP reduction is due to reduction in peripheral vascular resistance (afterload) against which the heart works. This reduces
oxygen demand by the heart and may account for its effectiveness in chronic stable angina.
Mild to moderate hypertension.
Severe hypertension, angina, CHF, pulmonary hypertension.
Hypersensitivity to felodipine; sick sinus rhythm or second- or third-degree heart block except with the use of a pacemaker;
abnormal aortic stenosis; hypotension; bradycardia; cardiogenic shock; acute MI; left ventricular dysfunction; pregnancy (category
C). Safety and efficacy in children are not established.
Hypotension, CHF, angina; aortic stenosis, cardiomyopathy; older adults; GERD; hiatal hernia; hepatic impairment; lactation.
Route & Dosage
Adult: PO 510 mg once/d (max: 20 mg/d)
Start older adults and patients with impaired liver function at 2.5 mg q.d.
- Give tablet whole. Do not crush or chew tablets.
- Store at or below 30° C (86° F) in a tightly closed, light-resistant container.
Adverse Effects (≥1%) Body as a Whole:
Most adverse effects appear to be dose dependent. CV:
Tachycardia, palpitations, flushing, peripheral edema. CNS: Dizziness, fatigue,
Nausea, flatulence, diarrhea
, dyspepsia. Hematologic:
Small but significant decreases in Hct, Hgb, and RBC count.
Diagnostic Test Interference
Serum alkaline phosphatase may be slightly but significantly increased. Plasma total and ionized calcium levels rise significantly. Serum gamma-glutamyl transferase may increase.
may cause prolonged bradycardia if it is used to treat patients with toxic concentrations of calcium channel blockers
. Carbamazepine, phenobarbital, phenytoin
may decrease felodipine bioavailability and serum
may increase felodipine bioavailability (competes for hepatic metabolism
). Concomitant felodipine and digoxin administration
produces only transient increases in plasma digoxin
concentrations (3540% increase), which are not sustained with continued administration
. This interaction may be
relevance in patients whose plasma digoxin
concentration is in the upper portion of the therapeutic range or in patients with preexisting renal
Completely absorbed from GI tract; it undergoes extensive first-pass metabolism
with only about 15% of dose reaching systemic
<1 h. Peak:
24 h. Duration:
2024 h (sustained release formulation). Distribution:
>99% bound to plasma proteins
Metabolized via hepatic
cytochrome P-450 mixed function oxidase system. Elimination:
6070% of metabolites are excreted in urine within 72 h. Half-Life:
Assessment & Drug Effects
- Monitor BP carefully, especially at initiation of drug therapy, in patients >64 y, and in those with impaired liver function.
- Anticipate BP reduction with possible reflex heart rate increase (510 bpm) 25 h after dosing.
- Report sustained hypotension promptly; more common with concurrent beta-blocker therapy.
- Assess for and report reflex tachycardia; may precipitate angina.
- Monitor patients for possible digoxin toxicity when taking concurrent digoxin.
- Report peripheral edema, headache, or flushing to physician. These may necessitate discontinuation of drug.
- Get up from lying down slowly and in stages; there is potential for dizziness and hypotension.