Which antihypertensive is preferred for acute severe hypertension in pregnancy when IV access is unavailable, and what is its mechanism?
- A Sublingual nifedipine; rapid reflex tachycardia via baroreceptor activation
- B Oral labetalol; combined α and β blockade
- C Oral nifedipine; L-type calcium channel blockade in vascular smooth muscle ✓
- D Oral methyldopa; centrally-acting α2 agonism
Explanation
Oral immediate-release nifedipine (10–20 mg) is the preferred agent for acute severe hypertension in pregnancy when IV access is unavailable, based on ACOG 2017 recommendations. It works by blocking voltage-gated L-type calcium channels in vascular smooth muscle, causing vasodilation and BP reduction within 20–30 minutes. Sublingual nifedipine (biting the capsule) is specifically contraindicated in pregnancy due to unpredictable absorption and risk of precipitous hypotension causing uteroplacental insufficiency. Methyldopa is a maintenance agent with slow onset, unsuitable for acute crises.
Reference: Williams Obstetrics, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.