Hypertensive disorders of pregnancy (HDP) may be managed with oral antihypertensives; however, pregnancy-induced changes in the hormonal milieu and volume of distribution make it difficult to determine optimal dosing regimens. Nifedipine is a first-line therapy for treatment of HDP. The purpose of this study is to compare 60 mg daily (QD) of extended released (XR) nifedipine to 30 mg twice daily (BID) for blood pressure (BP) control antepartum and postpartum.
This was a retrospective chart review conducted in Mount Sinai Health System. Patients admitted from January 1, 2015 to April 30, 2021, who were diagnosed with a HDP and received nifedipine XR 30 mg BID or 60 mg QD for intrapartum or postpartum BP control were included. The primary outcome was need for dose adjustment of nifedipine or addition of another antihypertensive agent. Patients were excluded if they had preexisting renal disease or were already taking oral antihypertensives.
Two hundred thirty-seven patients were included, 139 (59%) received 30 mg BID and 98 (41%) 60 mg QD. There was no statistically significant difference in the need for increase in nifedipine dose or addition of another oral antihypertensive between those receiving 30 mg BID versus 60 mg QD (33.8% versus 35.7%, adjusted odds ratio [95% CI], 0.90 [0.50, 1.60]; P=.71). Additionally, there was no difference in need for emergency hypertensive treatment after reaching study dose (P=.19) or readmission for BP control between the two groups (P>.99).
These findings suggest that BID versus QD dosing of nifedipine XR does not improve blood pressure control in the antepartum or postpartum periods; thus, daily dosing is reasonable and may be preferable for patient convenience and compliance.