Methyldopa. Mechanisms and treatment 25 years later.

Methyldopa, an adrenergic-inhibiting compound, has been used for over 25 years as a safe and effective antihypertensive agent. The postulated mechanisms for the antihypertensive action of this compound have been varied and parallel our broadening knowledge of the role of the adrenergic nervous system in controlling arterial pressure. This review outlines the mechanisms of adrenergic control of the circulation and how the proposed mechanisms of action of methyldopa (ie, dopa decarboxylation, false neurotransmission, inhibition of renin release, and stimulation of alpha receptor sites in the brain) seem to account for the depressor action of the drug. Physiologic effects as well as immunologic and other clinical effects are also discussed.