(174) Comparison of Antinausea Medications for Persistent Vomiting in Pregnancy Resistant to Doxylamine/Pyridoxine Regimens

Pregnant women experiencing nausea and vomiting in pregnancy (NVP) is a common occurrence, yet management approaches are highly varied among providers and specialties, with uncertainty arising when a patient fails initial doxylamine/pyridoxine treatment. This study sought to determine which alternative medication proved most effective for patients with persistent NVP following initial treatment with a doxylamine/pyridoxine regimen.

Study Design:

We conducted a multi-center, prospective observational study from 7/2021 to 7/2022 and included all pregnant women reporting a NVP refractory to doxylamine/pyridoxine in the prenatal period with gestational-age ranging from 24 0/7 through 36 6/7 weeks-gestation. The primary outcomes included need to switch medication and patient-reported resolution confirmed by provider assessment, as discrete events. Patients taking overlapping medications or with allergies to any included medications were excluded. Monotherapy oral medications including metoclopramide, odansetron, cyproheptadine and diphenhydramine were included as covariates. Medication choice was determined by physician preference.

Results:

The study included 777 patients diagnosed with NVP. Baseline demographic factors were not significantly different. Patients who received metoclopramide were less likely to need to switch to an alternative medication (57.1% v. 32.9%, p = 0.004). When adjusting for confounding factors including maternal age, gestational age, race, and composite medical history, these differences remained significant (RR 0.45, 95% CI 0.21-0.69, p = 0.002). Patients who received cyproheptadine were more likely to report improvement in appetite (62.4% v. 21.8%, p = < 0.001), which also remained significant after adjusting for confounders (RR 1.64, 95% CI 1.44-1.86, p = 0.001).

Conclusion:

Pregnant patients failing initial doxylamine/pyridoxine regimens may benefit from choosing metoclopramide as the next medication trial, with an extended potential benefit of cyproheptadine in patients specifically requiring assistance with stimulating appetite.