Overview
DESCRIPTION Isradipine is a calcium antagonist available for oral administration in capsules containing 2.5 mg or 5 mg. The structural formula of isradipine is: Chemically, isradipine is 3,5-Pyridinedicarboxylic acid, 4-(4-benzofurazanyl)-1,4-dihydro-2,6-dimethyl-,methyl 1-methylethyl ester. Isradipine is a yellow, fine crystalline powder which is odorless or has a faint characteristic odor.
Mechanism of Action
CLINICAL PHARMACOLOGY Mechanism of Action Isradipine is a dihydropyridine calcium channel blocker. It binds to calcium channels with high affinity and specificity and inhibits calcium flux into cardiac and smooth muscle. The effects observed in mechanistic experiments in vitro and studied in intact animals and man are compatible with this mechanism of action and are typical of the class. Except for diuretic activity, the mechanism of which is not clearly understood, the pharmacodynamic effects of isradipine observed in whole animals can also be explained by calcium channel blocking activity, especially dilating effects in arterioles which reduce systemic resistance and lower blood pressure, with a small increase in resting heart rate.
Indications
- INDICATIONS AND USAGE Hypertension Isradipine capsules are indicated in the management of hypertension. It may be used alone or concurrently with thiazide-type diuretics.
Common Doses
- 2.5 mg
- 5 mg
- 20 mg
- 10 mg
Dosage
DOSAGE AND ADMINISTRATION The dosage of isradipine should be individualized. The recommended initial dose of isradipine is 2.5 mg b.i.d. alone or in combination with a thiazide diuretic. An antihypertensive response usually occurs within 2 to 3 hours. Maximal response may require 2 to 4 weeks. If a satisfactory reduction in blood pressure does not occur after this period, the dose may be adjusted in increments of 5 mg/day at 2 to 4 week intervals up to a maximum of 20 mg/day.
Contraindications
- CONTRAINDICATIONS Isradipine is contraindicated in individuals who have shown hypersensitivity to any of the ingredients in the formulation.
Side Effects
- ADVERSE REACTIONS In multiple dose U.S. studies in hypertension, 1228 patients received isradipine alone or in combination with other agents, principally a thiazide diuretic, 934 of them in controlled comparisons with placebo or active agents. An additional 652 patients (which includes 374 normal volunteers) received isradipine in U.S. studies of conditions other than hypertension, and 1321 patients received isradipine in non-U.S. studies. About 500 patients received isradipine in long-term hypertension studies, 410 of them for at least 6 months.
Interactions
- Drug Interactions Nitroglycerin: Isradipine has been safely coadministered with nitroglycerin. Hydrochlorothiazide: A study in normal healthy volunteers has shown that concomitant administration of isradipine and hydrochlorothiazide does not result in altered pharmacokinetics of either drug. In a study in hypertensive patients, addition of isradipine to existing hydrochlorothiazide therapy did not result in any unexpected adverse effects, and isradipine had an additional antihypertensive effect.