These agents cause dilation of arteries throughout the body including mild dilatation of coronary arteries. They also cause a variable decrease in myocardial contractility that may lead to heart failure in susceptible individuals.
Dihydropyridines include amlodipine, felodipine, and, nifedipine. They are indicated for the management of hypertension. They may also be used for the treatment of stable angina, but only in combination with a beta-blocking drug that prevents an increase in heart rate and the increase in cardiac workload that may be caused by dihydropyridines. The common adverse effects include edema of the ankles, flushing, headaches, and rarely, hypertrophy of the gums. Other dihydropyridines include isradipine, nicardipine, nimodipine, nitrendipine, and niludipine.
1. Amlodipine (Norvasc)
This dihydropyridine has a long half-life of 35–50 h and peak blood levels are reached after 6–12 h. Amlodipine is an effective antihypertensive agent that is used worldwide. It has a good safety profile but pulmonary edema (heart The three major calcium antagonists include nifedipine, diltiazem, and verapamil (see Fig. 1 for their structural formulas). Dihydropyridine, the prototype of which is nifedipine, appears to act by plugging the calcium failure) may be precipitated in patients with severe left ventricular dysfunction and ejection fraction of less than 30%. Edema of the ankles, feet, and lower leg may be bothersome in about 10% of treated patients. This drug is often combined with a beta-blocker in the management of angina. The dose for angina or hypertension is 5–10 mg once daily.

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