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Table 23. Antihypertensive Agents Used for Urgent Blood
Pressure Control in Pregnancy
Drug Dose Comments Onset of Action
Labetalol 10–20 mg IV, then
20–80 mg every
10–30 min to a
maximum cumulative
dosage of 300 mg ; or
constant infusion 1–3
mg/min IV
Tachycardia is less
common with fewer
adverse effects.
Avoid in women with
asthma, preexisting
myocardial disease,
decompensated cardiac
function, and heart block
and bradycardia.
1–2 min
Hydralazine 5 mg IV or IM, then
5–10 mg IV every
20–40 min to a
maximum cumulative
dosage of 20 mg ; or
constant infusion of
0.5–10 mg/h
Higher or frequent dosage
associated with maternal
hypotension, headaches,
and abnormal fetal heart
rate tracings; may be more
common than other agents.
10–20 min
Nifedipine
(immediate
release)
10–20 mg orally,
repeat in 20 min if
needed; then 10–20
mg every 2–6 h;
maximum daily dose is
180 mg
May observe reflex
tachycardia and headaches.
5–10 min
IM indicates intramuscular; and IV, intravenous.
Reprinted with permission from American College of Obstetricians and Gynecologists.
Copyright © 2020 American College of Obstetricians and Gynecologists.
