Calcium channel blockers are widely used in the treatment of hypertension, angina pectoris, cardiac arrhythmias, and other disorders, and the longer-acting preparations have been prescribed with increasing frequency. A review of the major side effects associated with these agents and the previous controversy concerning their effect on coronary events, mortality, gastrointestinal bleeding, and the development of cancer are presented here. The management of calcium channel intoxication is presented separately. (See "Calcium channel blocker poisoning".)
TYPES OF CALCIUM CHANNEL BLOCKERS
While all calcium channel blockers inhibit the L-type calcium channel on cells, they are divided into two major categories based upon their predominant physiologic effects: the dihydropyridines, which are predominantly vasodilator and generally have neutral or increased effects on vascular permeability; and the non-dihydropyridines, such as verapamil and diltiazem, which reduce vascular permeability and affect cardiac contractility and conduction .
Dihydropyridines — The dihydropyridines are potent vasodilators that have little or no negative effect upon cardiac contractility or conduction. They can be further divided into three categories based upon half-life and effect on contractility:
- Short-acting (capsule containing liquid) nifedipine
- Longer-acting formulations with little cardiac depressant activity – felodipine, isradipine, nicardipine, nifedipine GITS and CC, and nisoldipine
- Long-acting agents with no cardiac depressant activity – amlodipine, lacidipine
Non-dihydropyridines — Verapamil and, to a lesser extent, diltiazem are somewhat less potent vasodilators, but they have a greater depressive effect on cardiac conduction and contractility compared to dihydropyridines. (See "Calcium channel blockers in the treatment of cardiac arrhythmias".)