Table III.

 Drugs for Urgent Control of Severe Hypertension in Pregnancy

Drug (Food and Drug Administration Risk)a	Dose and Rate	Concerns or Commentsb
Labetalol (C)	20 mg IV, then 20–80 mg every 20–30 min, up to a maximum of 300 mg; or constant infusion of 1–2 mg/min	Experience in pregnancy less than with hydralazine; probably less risk for tachycardia and arrhythmia than with other vasodilators
Hydralazine (C)	5 mg IV or IM, then 5–10 mg every 20–40 min; or constant infusion of 0.5–10 mg/h	Drug of choice according to NHBEP working group; long experience of safety and efficacy
Nifedipine (C)	Tablets recommended only; 10–30 mg orally, repeat in 45 minutes if needed	Possible interference with labor
Relatively contraindicated nitroprusside (C)c	Constant infusion of 0.5–10 g/kg/min	Possible cyanide toxicity; agent of last resort

Note: Indicated for acute increase of diastolic blood pressure ≥105 mm Hg; goal is a gradual reduction to 90/100 mm Hg. C indicates that either studies in animals have revealed adverse effects on the fetus (teratogenic, embryocidal, or other), that there are no controlled studies in women, or studies in women and animals are not available. Drugs should be given only if the potential benefits justify the potential risk to the fetus. Abbreviations: IM, intramuscularly; IV, intravenously; NHBEP, National High Blood Pressure Education Program. ^aUS Food and Drug Administration classification. ^bAdverse effects for all agents, except as noted, may include headache, flushing, nausea, and tachycardia (primarily caused by precipitous hypotension and reflex sympathetic activation). ^cWe would classify as category D; there is positive evidence of human fetal risk, but the benefits of use in pregnant women may be acceptable despite the risk (eg, if the drug is needed in a life‐threatening situation or for a serious disease for which safer drugs cannot be used or are ineffective). Reprinted with permission from Lindheimer et al. ¹⁴