Isradipine.

Isradipine is a potent dihydropyridine calcium channel blocker. It is highly selective for vascular smooth muscle, with very few negative inotropic or chronotropic effects. It may have minor depressant effects on the sinoatrial node, hence reducing the incidence of reflex tachycardia. The drug is extensively metabolized in the liver, with several pharmacologically inactive metabolites. As the elimination half-life is about 9 h the drug is usually given twice daily, but a once-daily modified release form is under investigation. Isradipine is effective monotherapy in essential hypertension, and has been successfully combined with pindolol and captopril. On the basis of more limited evidence it also appears to be beneficial in stable angina and in congestive cardiac failure. A trial is also under way to assess its antiatherogenic properties. Adverse effects are those predicted for a vasodilator calcium antagonist, and may be less frequent than for equivalent doses of nifedipine. This needs to be confirmed by more extensive clinical experience. Overall, isradipine can be considered favourably in essential hypertensives where a calcium channel blocker is indicated, particularly if it is desirable to avoid myocardial depression or to minimize reflex tachycardia. Its role in other cardiovascular disease awaits further evaluation.