What are safe medications for nausea and vomiting during pregnancy?

Safe Medications for Nausea and Vomiting During Pregnancy

For nausea and vomiting during pregnancy (NVP), first-line pharmacological treatment should include vitamin B6 (pyridoxine) and doxylamine, which are FDA-approved, safe, and effective options when non-pharmacological approaches are insufficient. 1

Treatment Algorithm for NVP

Step 1: Non-pharmacological Approaches

• Begin with diet and lifestyle modifications 1:
  • Eat small, frequent, bland meals (e.g., BRAT diet - bananas, rice, applesauce, toast) 1
  • Choose high-protein, low-fat meals 1
  • Identify and avoid specific food triggers and strong odors 1

Step 2: First-Line Pharmacological Treatment

• Ginger 250 mg capsules four times daily 1
• Vitamin B6 (pyridoxine) 10-25 mg every 8 hours 1, 2
• Doxylamine 10 mg (available in combination with pyridoxine as FDA-approved therapy) 1, 3
• Combination of doxylamine and pyridoxine (10 mg/10 mg or 20 mg/20 mg) is safe, well-tolerated, and FDA-approved 1, 3

Step 3: Second-Line Pharmacological Treatment

• H1-receptor antagonists are considered safe first-line pharmacologic antiemetic therapies 1:
  • Promethazine 1, 4
  • Dimenhydrinate 1, 4

Step 4: For Moderate to Severe Cases

• Ondansetron may be used, though with caution in early pregnancy 1
  • Small risk of cleft palate (0.03% absolute increase) and cardiovascular malformations (0.3% increase in ventricular septal defects) 1
• Metoclopramide 5-10 mg orally every 6-8 hours 1
  • Meta-analysis of 33,000 first-trimester exposures showed no significant increase in major congenital defects 1
• Glucocorticosteroids for severe cases 1:
  • Avoid before 10 weeks gestation due to increased risk of oral clefts 1
  • After 10 weeks, methylprednisolone or prednisolone are preferred 1

Safety Considerations

Vitamin B6 and Doxylamine

• Highest safety profile (FDA Pregnancy Category A) 3
• Extensive safety data accumulated over decades 3
• Combination therapy is safe and well-tolerated 1

Ondansetron

• Use with caution in early pregnancy 1
• Small but statistically significant risk of orofacial clefts and cardiac defects 1
• Consider for moderate to severe cases when first-line treatments fail 1

Metoclopramide

• Generally considered safe based on large cohort studies 1
• No significant increase in congenital malformations 1

Corticosteroids

• Avoid before 10 weeks gestation 1
• Choose methylprednisolone or prednisolone which are metabolized in the placenta 1
• Avoid dexamethasone and betamethasone due to nearly 100% placental passage 1

Clinical Pearls

• Early intervention is key to prevent progression to hyperemesis gravidarum (HG) 1
• Severity of NVP can be quantified using the Motherisk Pregnancy Unique Quantification of Emesis (PUQE) score 1
• NVP typically begins at 4-6 weeks, peaks at 8-12 weeks, and resolves by week 20 1
• For severe cases (hyperemesis gravidarum), hospitalization may be required for IV hydration and more aggressive antiemetic therapy 1
• Avoid NK-1 antagonists (aprepitant) and second-generation antipsychotics (olanzapine) unless absolutely necessary due to limited safety data 1