Comparison of clonidine and methyldopa on blood pressure and side effects in hypertensive patients

Abstract

Clonidine hydrochloride (Catapres) represents a new type of antihypertensive agent which acts to reduce blood pressure by central inhibition of sympathetic vasomotor and cardioexcitatory stimuli. 1,2 We have previously demonstrated its antihypertensive effectiveness particularly when combined with a diuretic. 3 The drug has been shown to have long-term effectiveness in the treatment of severe hypertension and sufficient potency to replace guanethidine. Sedation, constipation, and dry mouth are its chief side effects; they tend to decrease with the passage of time and are less objectionable than the fatigue and postural syncope frequently seen with guanethidine. 4 Clonidine is also useful in smaller doses in the treatment of less severe forms of hypertension, where other antihypertensive drugs such as alpha methyldopa may also be effective. The purpose of the present study is to compare these two drugs at a fixed dosage, both concerning their hypotensive effectiveness in patients with moderately severe hypertension and also concerning side effects produced by each agent when the blood pressure is lowered to a comparable degree.