Cardene SR (Nicardipine Hydrochloride) - Drug Interactions, Contraindications, Overdosage, etc

DRUG INTERACTIONS

Beta-Blockers

In controlled clinical studies, adrenergic beta-receptor blockers have been frequently administered concomitantly with CARDENE. The combination is well tolerated.

Cimetidine

Cimetidine increases CARDENE plasma levels. Patients receiving the two drugs concomitantly should be carefully monitored.

Digoxin

Some calcium blockers may increase the concentration of digitalis preparations in the blood. CARDENE usually does not alter the plasma levels of digoxin; however, serum digoxin levels should be evaluated after concomitant therapy with CARDENE is initiated.

Fentanyl Anesthesia

Severe hypotension has been reported during fentanyl anesthesia with concomitant use of a beta-blocker and a calcium channel blocker. Even though such interactions were not seen during clinical studies with CARDENE, an increased volume of circulating fluids might be required if such an interaction were to occur.

Cyclosporine

Concomitant administration of nicardipine and cyclosporine results in elevated plasma cyclosporine levels. Plasma concentrations of cyclosporine should therefore be closely monitored, and its dosage reduced accordingly, in patients treated with nicardipine.

When therapeutic concentrations of furosemide, propranolol, dipyridamole, warfarin, quinidine or naproxen were added to human plasma (in vitro), the plasma protein binding of CARDENE was not altered.

OVERDOSAGE

Three overdosages with CARDENE or CARDENE SR have been reported. Two occurred in adults, 1 of whom ingested 600 mg of CARDENE and the other 2160 mg of CARDENE SR. Symptoms included marked hypotension, bradycardia, palpitations, flushing, drowsiness, confusion, and slurred speech. All symptoms resolved without sequelae. The third overdosage occurred in a 1-year-old child who ingested half of the powder in a 30-mg CARDENE capsule. The child remained asymptomatic.

Based on results obtained in laboratory animals, overdosage may cause systemic hypotension, bradycardia (following initial tachycardia) and progressive atrioventricular conduction block. Reversible hepatic function abnormalities and sporadic focal hepatic necrosis were noted in some animal species receiving very large doses of nicardipine.

For treatment of overdose standard measures (for example, evacuation of gastric contents, elevation of extremities, attention to circulating fluid volume, and urine output) including monitoring of cardiac and respiratory functions should be implemented. The patient should be positioned so as to avoid cerebral anoxia. Frequent blood pressure determinations are essential. Vasopressors are clinically indicated for patients exhibiting profound hypotension. Intravenous calcium gluconate may help reverse the effects of calcium entry blockade.

CONTRAINDICATIONS

CARDENE is contraindicated in patients with hypersensitivity to the drug.

Because part of the effect of CARDENE is secondary to reduced afterload, the drug is also contraindicated in patients with advanced aortic stenosis. Reduction of diastolic pressure by any means in these patients may worsen rather than improve myocardial oxygen balance.