Regular formulation and sustained-release verapamil therapy in normotension and in mild to moderate hypertension.
Calcium entry blocker drugs have hypotensive effects that are mediated by both cardiac and noncardiac actions. Dihydropyridine calcium blockers, such as nifedipine and nicardipine, are potent vascular smooth muscle relaxants that lower blood pressure by decreasing peripheral arteriolar resistance. Reflex tachycardia, however, may blunt the magnitude of their hypotensive effect, especially in patients with increased baroreflex sensitivity. Nondihydropyridine calcium blocker drugs, such as verapamil and diltiazem, exert their hypotensive action by both cardiac and peripheral circulatory mechanisms. These drugs also act as arteriolar vasodilators. In addition, they slow the heart rate by decreasing the automaticity of sinoatrial pacemaker cells in the heart. The combined negative chronotropic and vasodilatory actions are especially useful in hypertensive patients with baroreflex sensitivity who are prone to fast heart rates, and in hypertensive patients with associated coronary artery disease. Coronary heart disease patients with or without coexisting hypertension usually show reduction in systolic blood pressure (SBP) and heart rate (HR) both at rest and during submaximal exercise on the treadmill or bicycle. A reduced double product (SBP X HR) with submaximal exertion results in a decrease in cardiac work and correlates with enhanced exercise capacity and delay in onset of angina during exercise testing. In some patients with both hypertensive and coronary heart diseases and ventricular dysrhythmias emerging during exercise, verapamil may confer antiarrhythmic as well as antihypertensive and antianginal benefits. At present, calcium blocker drugs, which have an elimination half-life of 3 to 6 hours, must be given 3 times a day for effective antihypertensive control.(ABSTRACT TRUNCATED AT 250 WORDS)
D000787:Angina Pectoris / Q000188:drug therapy* / Q000503:physiopathology; D002986:Clinical Trials as Topic; D003692:Delayed-Action Preparations; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion; D011446:Prospective Studies; D011897:Random Allocation; D014700:Verapamil / Q000008:administration & dosage* / Q000494:pharmacology
D003692:Delayed-Action Preparations; D014700:Verapamil