ABSTRACT
Plasma level monitoring of antihypertensive agents will be especially beneficial in cases of unusual drug toxicity, apparent drug resistance, and in patients with kidney or liver disorders with a potential to develop adverse drug reactions. Reserpine acts by a complex mechanism which is not fully understood. Part of the antihypertensive effect of reserpine is via depletion of endogenous catecholamine stores of the postganglionic adrenergic neurons and the adrenal medulla. Clonidine, a potent antihypertensive agent, lowers blood pressure and heart rate by stimulating postsynaptic a-adrenergic receptors in the central nervous system. Blockade of β-adrenergic receptors was first noted in 1964 by Pritchard to produce an antihypertensive effect in man. The mechanism of antihypertensive action of loop diuretics is probably similar to that of thiazides. The antihypertensive effect of indapamide, a nonthiazide sulfonamide, is produced by lowering of peripheral vascular resistance as a result of a decrease in arteriolar hyperreactivity to vasopressor amines. Indapamide has a prolonged blood pressure-lowering effect.
