Methyldopa remains widely used for chronic hypertension in pregnancy because of its established fetal safety profile. Its antihypertensive mechanism is best described as:

• A Direct arterial vasodilatation independent of sympathetic tone
• B Competitive blockade of vascular alpha-1 receptors
• C Central alpha-2 adrenergic agonism via its metabolite alpha-methylnorepinephrine ✓
• D Inhibition of angiotensin converting enzyme in the pulmonary circulation

Explanation

Methyldopa is converted centrally to alpha-methylnorepinephrine, a false neurotransmitter that stimulates central alpha-2 adrenergic receptors, reducing sympathetic outflow and lowering blood pressure. It does not impair uteroplacental perfusion and decades of use show no increased fetal malformation risk. Direct vasodilation describes hydralazine, alpha-1 blockade describes prazosin, and ACE inhibition is contraindicated in pregnancy because of fetal renal toxicity. Sedation and depression are its main limiting side effects, prompting many clinicians to switch agents after delivery.

Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.