MOXONIDINE - A REVIEW OF ITS PHARMACOLOGY, AND THERAPEUTIC USE IN ESSENTIAL-HYPERTENSION

Interest in centrally acting antihypertensive agents has recently been renewed with the development of drugs that are associated with fewer central adverse effects (e.g. sedation, dry mouth) than the older drugs in this class. Moxonidine reduces sympathetic outflow and hence lowers blood pressure through stimulation of central imidazoline receptors. Blood pressure is decreased by 10 to 20% during moxonidine treatment, with about 70% of patients with mild to moderate hypertension achieving a diastolic pressure of < 90mm Hg. The relatively few published comparative studies demonstrate that moxonidine has efficacy comparable with that of clonidine, prazosin, atenolol, nifedipine, captopril and hydrochlorothiazide. It is at least as well tolerated as these agents in trials and, importantly, appears to cause less sedation and dry mouth than clonidine. Compliance may be aided by the once- or twice-daily administration schedule with moxonidine, and dosage adjustment is only necessary in patients with moderate renal impairment. While its published clinical data base needs further expanding, moxonidine thus appears to be a more attractive option than oral clonidine, and may be considered along with the other classes of drug used to treat patients with mild to moderate hypertension.