Clinical Experiences of Intravenous Hydralazine and Labetalol for Acute Treatment of Severe Hypertension in Pregnant Thai Women

Abstract

Response to acute treatment of severe hypertension during pregnancy in Asian women was not known. Labor and delivery checklists of Thai women treated with intravenous hydralazine or labetalol for systolic blood pressure (SBP) ≥ 160 or diastolic blood pressure (DBP) ≥ 110 mm Hg from January 2011 to December 2013 were reviewed as parts of an audit. Primary outcome was prompt achievement of SBP 140-150 and DBP 90-100 mm Hg after the first bolus. Secondary outcomes were medication-related undesired effects. The mean ± standard deviation age and prevalence of chronic hypertension in hydralazine (n = 62) versus labetalol (n = 64) groups were 32.5 ± 6 versus 29.9 ± 6.8 years and 50% versus 21.9%, respectively (P < .05). Magnesium sulfate was promptly administered on admission to every woman to prevent seizure. Targeted blood pressure was timely achieved in 41.9% and 67.2% of the hydralazine and labetalol groups, respectively (P < .05). Nonreassuring fetal heart rate occurred in 51.6% and 32.8% of the hydralazine and labetalol groups, respectively (P = .05). The prevalence of cesarean section and Apgar score < 7 were not significantly different (P > .05). Real-life clinical experiences suggested significant advantages of intravenous labetalol over hydralazine in pregnant women with severe hypertension.

Pharmaceutical administration for severe hypertension during pregnancy: Network meta-analysis

“…Labetalol is a selective a -1, non-selective β-adrenoceptor blocker that induces peripheral vasodilation and prevented reflex tachycardia that can rapidly reduce peripheral blood resistance and blood pressure, but the variations on heart rate or urine volume were not significant ( Chera-Aree et al, 2020 ; Wu et al, 2020 ). Hydralazine is an effective direct arteriolar vasodilator that can reduce peripheral blood pressure resistance, mediate the release of adrenalin and norepinephrine receptors, and increase cardiac output and venous return flow ( Herman et al, 2022 ).…”

“…Hydralazine is an effective direct arteriolar vasodilator that can reduce peripheral blood pressure resistance, mediate the release of adrenalin and norepinephrine receptors, and increase cardiac output and venous return flow ( Herman et al, 2022 ). Furthermore, the pharmaceutical itself could reduce systemic resistance, which has long been used for rapid controlling of severe hypertension during pregnancy ( Chera-Aree et al, 2020 ). Nifedipine is suitable for all kinds of hypertension, especially severe hypertension ( Zhao et al, 2020 ).…”

“…The possible reason is that the dose-response of hydralazine was largely unpredictable and may ultimately lead to an unpredicted response to blood pressure ( Cawoski et al, 2021 ). In addition, the pharmaceutical had long been used for rapid control of severe hypertension during pregnancy ( Chera-Aree et al, 2020 ). In another study ( Khan et al, 2017 ), reduction of blood pressure with labetalol was significant than hydralazine, possibly that the reduction in blood pressure control is related to the dosages of this pharmaceutical used ( Zhang et al, 2021 ) and the maximum permissible dosages was 300 mg/day ( Peacock et al, 2012 ).…”

Comparison of outcomes following intravenous magnesium compared with intravenous labetalol and oral nifedipine in 355 pregnant Han Chinese women with preeclampsia

“…[17] A total of 115 women received 20 mg intravenously over 2 minutes initially, then 40-80 mg intravenous after 10 min intervals labetalol; the total dose of labetalol did not exceed 200 mg/day (labetalol [LB] cohort). [12] A total of 136 women received 20 mg extended-release nifedipine 3 times a day for a maximum of 7 days (nifedipine [NF] cohort). [8] The choice of intravenous magnesium sulfate, intravenous labetalol, or oral extended-release nifedipine therapy was at the discretion of the attending obstetrician(s) but therapy follows institutional protocol (not published yet) for the management of preeclampsia in the pregnant women.…”

“…[13] The management of preeclampsia is a balance between risk and associated therapy-related toxic effects in cardiovascular diseases. [12] Oral nifedipine is generally used by obstetricians in pregnant women for the management of hypertension in preeclampsia but it has slower management of hypertension and the effects are not last long. [14]…”