Treatment of Nausea and Vomiting in Pregnancy with Diclegis (Doxylamine-Pyridoxine)
Diclegis (doxylamine succinate 10 mg and pyridoxine hydrochloride 10 mg) is the first-line pharmacologic treatment for nausea and vomiting of pregnancy (NVP) when non-pharmacologic approaches are insufficient, and is currently the only FDA-approved medication specifically for this indication. 1
Assessment of Severity
Before initiating treatment, assess severity using the Motherisk Pregnancy-Unique Quantification of Emesis (PUQE) score:
| Severity | PUQE Score |
|---|---|
| Mild | ≤6 |
| Moderate | 7-12 |
| Severe | ≥13 |
Treatment Algorithm
Step 1: Non-pharmacologic Approaches
- Diet modifications:
- Small, frequent, bland meals
- BRAT diet (bananas, rice, applesauce, toast)
- High-protein, low-fat meals
- Avoid spicy, fatty, acidic, and fried foods
- Identify and avoid specific triggers (foods with strong odors, activities)
Step 2: First-Line Pharmacologic Treatment
When non-pharmacologic measures fail, initiate Diclegis:
Dosing Protocol:
- Start with 2 tablets at bedtime
- If symptoms persist, add 1 tablet in the morning
- If needed, add 1 additional tablet in the afternoon (maximum 4 tablets daily)
The delayed-release formulation is designed to provide symptom control throughout the day when taken as directed.
Step 3: Dose Adjustments
- Evaluate response after 4-5 days (efficacy is typically established by this time) 2
- If inadequate response with 4 tablets daily, consider adding or switching to alternative agents
Step 4: Alternative or Additional Agents (for inadequate response)
- Ginger (250 mg capsules 4 times daily) 1
- Metoclopramide (5-10 mg orally every 6-8 hours) 1
- Ondansetron (consider after 10 weeks gestation due to small risk of orofacial clefts) 1
- Methylprednisolone (for severe, refractory cases) 1
Efficacy and Safety
Diclegis has demonstrated efficacy in reducing NVP symptoms compared to placebo, with improvement typically seen within 3-5 days of treatment initiation 2. While the magnitude of benefit varies across studies, the combination has shown consistent symptom improvement 3.
The safety profile of Diclegis is well-established:
- FDA Pregnancy Category A status (one of few medications with this designation) 4
- No increased risk of major congenital malformations 5
- Most common side effects are drowsiness and fatigue 6
Special Considerations
Timing of administration: The delayed-release formulation works best when taken at bedtime, allowing the medication to be available upon waking when symptoms may be most severe.
Duration of therapy: NVP typically begins at 4-6 weeks, peaks at 8-12 weeks, and subsides by week 20 of pregnancy 1. Treatment duration should be individualized based on symptom persistence.
Side effect management: Take with food to reduce nausea and vomiting that may be associated with the medication itself 1.
Hyperemesis gravidarum: For women who progress to hyperemesis gravidarum (intractable vomiting, >5% weight loss, dehydration, electrolyte imbalances), hospitalization for IV hydration and more aggressive antiemetic therapy may be required 1.
Common Pitfalls to Avoid
Inadequate dosing: Starting with only 1 tablet daily is insufficient; the recommended starting dose is 2 tablets at bedtime.
Premature discontinuation: Efficacy should be assessed after at least 4-5 days of treatment.
Delayed treatment: Early intervention is critical to prevent progression to hyperemesis gravidarum 1.
Overlooking drug interactions: While uncommon, be aware of potential increased CNS depression when combined with other CNS depressants.
Insufficient patient education: Patients should be informed about the expected delayed onset of action and the importance of taking the medication as prescribed, even if symptoms temporarily improve.