Be ready to manage SEVERE gestational hypertension
As a clinical pharmacist, you will see more emphasis on urgent treatment of women hospitalized with SEVERE gestational hypertension. Women with gestational hypertension have normal blood pressure (BP) before pregnancy, and develop BPs of at least 140/90 mmHg after 20 weeks' gestation. It's severe when acute-onset BPs reach 160/110 mmHg or higher.
We know to admit and urgently treat women with "preeclampsia with severe features", gestational hypertension AND thrombocytopenia, liver or renal dysfunction, pulmonary edema, new-onset headache, or vision changes. Now treat SEVERE gestational hypertension ALONE with equal urgency. This is because high BPs are associated with maternal risks, such as stroke and fetal risks, such as low birth weight.
Start treatment ASAP, ideally within 30 to 60 min. Consider an IV labetalol bolus or oral IR nifedipine first. Examples of IV labetalol dosing:
- Bolus 20 mg IV once, then 40 mg IV after 10 min, then 80 mg IV after 10 min, if needed.
- Bolus 10 to 20 mg IV once, then 20 to 80 mg IV q10 to 30 min, to a max daily dose of 300 mg, or infusion 1 mg to 2 mg per minute.
Aim for BP under 160/110 mmHg initially, then keep at 140-150/90-100 mmHg. Lowering BP further could reduce placental perfusion. Monitor BP and fetal activity closely. Once BP is stable, check it every 10 to 15 minutes, then gradually extend the interval. If BP isn't at goal after a few doses, switch to the other medication or IV hydralazine. Examples of IV hydralazine dosing:
- Bolus 5 to 10 mg IV once, then 10 mg IV after 20 min, if needed.
- Bolus 5 mg IV once, then 5 to 10 mg IV q20 to 40 min, to a max daily dose of 20 mg.
- Infusion 0.5 mg to 10 mg per hour. Hydralazine works well but may cause more hypotension.
Don't use IV magnesium to lower BP, but give it to reduce the risk of seizures in women with preeclampsia with severe features. It's too soon to know the benefit of IV magnesium with severe gestational hypertension ALONE, but some experts feel it outweighs risk. If delivery will be delayed, expect to start scheduled oral medications, such as labetalol or extended-release nifedipine. Ensure initial BP medications are available on the unit for quick turnarounds. Be aware, The Joint Commission is proposing new perinatal standards, which include urgent management of severe gestational hypertension.
References
- ACOG Practice Bulletin No. 202: Gestational Hypertension and Preeclampsia. Obstet Gynecol. 2019 Jan;133(1):1.
- Sridharan K, Sequeira RP. Drugs for treating severe hypertension in pregnancy: a network meta-analysis and trial sequential analysis of randomized clinical trials. Br J Clin Pharmacol. 2018 Sep;84(9):1906-1916.
- Zulfeen M, Tatapudi R, Sowjanya R. IV labetalol and oral nifedipine in acute control of severe hypertension in pregnancy-A randomized controlled trial. Eur J Obstet Gynecol Reprod Biol. 2019 May;236:46-52.
