Doxylamine
UNISOM
Pronunciation: dox-IL-a-meen
“Un's somnolent Doxies”
Mad hatter hat → anticholinergic delirium
Crimson theme → anticholinergic
What it isFirst-generation H1 antagonist; insomnia, and with pyridoxine for nausea of pregnancy.
Why this onePyridoxine combination is the only FDA-approved treatment for nausea and vomiting of pregnancy.
What limits itAnticholinergic burden and next-day sedation. Tolerance to the hypnotic effect develops quickly.
Doxylamine prescription history
Animated chart of estimated U.S. prescriptions per year, H1 antihistamines (1944–2026). Doxylamine enters in 1949 (estimated).
FDA-approved for
- insomnia (~1948)
Principal riskAnticholinergic burden and next-day sedation
Classes and tags
Clinical profile
Defining liabilityResidual sedation and antimuscarinic effects
FDA label
Read the full label on DailyMed ↗
NO BOXED WARNINGS
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Insomnia (OTC nighttime sleep aid) | Adults & children ≥12 y | 1 tablet QHS PRN | 1 tablet QHS | 1 tablet/day |
Renal Undefined
Hepatic Undefined
Instructions
- Take one tablet 30 minutes before going to bed.
- Do not use in children under 12 years of age.
Available strengths
- tab 25 mg
- cap 6.25 mg
- sol 6.25 mg/15 mL
- sol 9.78 mg/3 mL
Pregnancy Undefined
Lactation Undefined
Cost
| Strength | #/mo | generic $/unit | CostPlus | |
|---|---|---|---|---|
| 25 mg | tab | per unit | $0.12/ea | not offered |
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Memory aids: interaction avatars
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Self-check
- Which vitamin pairs with doxylamine for pregnancy nausea?
Pyridoxine. - How quickly does tolerance to doxylamine’s hypnotic effect develop?
Quickly.