Hypotensive drugs

Abstract

This chapter discusses hypotensive drugs used for the treatment hypertension. The chapter discusses captopril. A number of compound preparations of β -adrenoceptor antagonists and diuretics are also marketed recently and some of their pros and cons are discussed. Captopril (D-3-mercapto-2-methylpropanoyl-L-proline) is the first available orally active converting enzyme inhibitor. In addition to blocking the conversion of angiotensin I to angiotensin II it also inhibits kininase II, which degrades bradykinin. It may also stimulate prostaglandin production or release. Its use is associated with a rise in plasma renin activity, a fall in plasma aldosterone concentrations with increased urinary sodium clearance and a rise in renal blood flow. It causes a fall in peripheral vascular resistance. The chapter discusses rebound hypertension due to drug withdrawal. This syndrome implies a precipitous rise in blood pressure following abrupt discontinuation of therapy. It occurs within 48 hours of suspension of the drug, is associated with symptoms and signs of sympathetic overactivity, blood pressure readings in excess of those recorded prior to treatment, and sequelae of sudden hypertension such as stroke or hypertensive encephalopathy.