Calcium Channel Blockers
Calcium channel blockers are popular group of antihypertensives. They are widely prescribed alone or in combination with other drugs.
The active substance acts on cellular calcium channels in the muscle cells of the heart and blood vessels. The result is relaxation of vascular muscle, which decreases the blood pressure. Cardiac muscle is affected as well by decreasing the cardiac load and cardiac output.
Calcium channel blockers are divided into two basic groups:
Non-dihydropyridine calcium channel blockers
This is the first generation of calcium channel blockers. Besides reduction of the blood pressure, these substances significantly decrease the heart rate. Used substances are verapamil and diltiazem.
Dihydropyridine calcium channel blockers
This group includes more modern calcium channel blockers that are used in the majority of patients. Active substances are for example amlodipine, nitrendipine, felodipine, isradipine and lacipidine.
Calcium channel blockers should not be administered to pregnant and lactating women, in patients with acute heart failure and in some forms of significant heart valve disease. The drugs can cause headache and their typical side-effect is leg swelling. Non-dihydropyridine agents can cause bradycardia and they should never be combined with beta-blockers.