From the Guidelines
Labetalol, methyldopa, and nifedipine are the primary antihypertensives used to treat severe hypertension in preeclampsia, as recommended by the most recent guidelines 1. For acute management, intravenous labetalol or oral methyldopa are first-line options, with nifedipine as an alternative.
- Labetalol can be administered intravenously (20-40 mg initially, then 20-80 mg every 10-30 minutes, maximum 300 mg) or orally (200-800 mg twice daily).
- Methyldopa can be administered orally (250-500 mg 2-3 times daily).
- Nifedipine can be administered orally (10-20 mg every 4-6 hours, extended-release 30-60 mg daily). Treatment should be initiated when blood pressure exceeds 160/110 mmHg to prevent cerebrovascular complications. These medications are preferred because they effectively lower blood pressure while maintaining uteroplacental blood flow and have established safety profiles in pregnancy. ACE inhibitors, ARBs, and direct renin inhibitors are contraindicated due to fetal toxicity. The goal is to maintain blood pressure between 140-150/90-100 mmHg, balancing maternal safety against the risk of compromising placental perfusion with excessive blood pressure reduction, as supported by recent studies 1. It is essential to note that the management of hypertension in pregnancy requires careful consideration of both maternal and fetal well-being, and treatment should be individualized based on the specific clinical scenario, as emphasized in the guidelines 1.
From the Research
Antihypertensives Used to Treat Preeclampsia
The following antihypertensives are used to treat preeclampsia:
- Nifedipine: a calcium channel blocker that can be administered orally 2, 3, 4, 5
- Labetalol: a beta-blocker that can be administered intravenously 2, 3, 6, 4, 5
- Hydralazine: an arteriolar vasodilator that can be administered intravenously 3, 6, 4
- Magnesium sulfate: used for the prevention and control of maternal seizures in patients with severe preeclampsia or eclampsia 6, 5
- Methyldopa: an alpha-2 adrenergic agonist that can be administered orally for chronic or mild hypertension 6, 4
- Diazoxide: a vasodilator that can be used for hypertensive emergencies 4
- Sodium nitroprusside: a vasodilator that can be used for life-threatening hypertension that does not respond to more conventional therapy 4
Comparison of Antihypertensives
Studies have compared the effectiveness of these antihypertensives in reducing blood pressure in patients with preeclampsia:
- Nifedipine and labetalol were found to be effective in reducing blood pressure, with nifedipine acting faster 2
- Labetalol was found to be more effective than nifedipine and magnesium sulfate in reducing blood pressure 5
- Hydralazine was found to be effective in reducing blood pressure, but may cause unpredictable hypotension 6
- Magnesium sulfate is the gold standard for the management of preeclampsia, but has a short action time and may not provide stable maintenance of blood pressure 5