Candesartan cilexetil: pharmacological properties and protective effects against organ damage of a novel nonpeptide angiotensin II-receptor antagonist

Abstract

The nonpeptide angiotensin II (AII) subtype-1 (AT1) receptor antagonist candesartan cilexetil is completely converted to its active form, candesartan, during gastrointestinal absorption. In in vitro studies, candesartan has been found to act as an insurmountable antagonist at the AT1 receptor that dose-dependently reduces the maximal contractions induced by AII and, at high concentrations, virtually eliminates the AT1-receptor-mediated effects of AII. Receptor binding studies suggest that insurmountable antagonism may be due to tight binding to the AT1 receptor and slow dissociation from it. The antihypertensive efficacy of candesartan cilexetil has been demonstrated in different animal models of hypertension. Candesartan cilexetil exerts a long-lasting antihypertensive action in spontaneously hypertensive rats in the low dose range of 0.1-10 mg/kg. The long-lasting antihypertensive effect of candesartan cilexetil is confirmed by the trough/peak ratio in hypertensive patients. It has been demonstrated that administration of AII receptor antagonists is followed by a rise in AII levels, and the increased AII levels result in competition with the antagonist for binding to the receptor. Insurmountable antagonists would seem to be more advantageous since they would block more efficiently in the presence of increasing AII levels than surmountable antagonists. A growing number of studies indicate that candesartan cilexetil provides end-organ protection in addition to lowering blood pressure. The utility of AT1 antagonists may extend beyond treatment of hypertension, chronic heart failure and renal diseases, as suggested by the potential usefulness of ACE inhibitors in the treatment or prevention of many other cardiovascular diseases.