What is Doxylamine used for?

Doxylamine is evaluated for the following indications with varying evidence strength: Nausea and vomiting in pregnancy (evidence tier A), Insomnia and sleep disorders (evidence tier D). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Doxylamine?

Common side effects of Doxylamine (≥ 1 in 100): Drowsiness and sedation, Dry mouth, Constipation, Blurred vision, Urinary retention (especially in older adults), Dizziness. See the Safety section for uncommon and serious reactions.

Is Doxylamine safe during pregnancy?

FDA category A. FDA Category A for the doxylamine + pyridoxine combination in pregnancy nausea. The most studied antiemetic group in pregnancy – over 200,000 exposures in meta-analyses with no teratogenic signal. AEMPS and SEGO authorise use from the first trimester. The drug is continued in hyperemesis, with dose escalation up to 4 capsules per day.

Is Doxylamine compatible with breastfeeding?

Not preferred. Hale L4. First-generation antihistamines suppress lactation and transfer into milk. The infant may experience drowsiness, poor sucking and irritability. eLactancia – «raised risk»; second-generation antihistamines (loratadine, cetirizine) are preferred when needed.

Who should not take Doxylamine?

Doxylamine is contraindicated in: Hypersensitivity to doxylamine or ethanolamine antihistamines; Narrow-angle glaucoma; Prostatic hypertrophy with urinary retention; Age under 6 years (without prescription supervision); Severe hepatic impairment. Full list in the Safety section.

Doxylamine

AEMPS

First-generation antihistamine (ethanolamine); antiemetic in combination with pyridoxine

ATC code: A04AD51 (Doxylamine + pyridoxine)

Brand names

Unisom, Diclegis, Bonjesta

Mechanism of action

H1-histamine receptor blocker with marked CNS penetration. Also blocks muscarinic M1 receptors – producing anticholinergic effects (dry mouth, urinary retention, constipation). Sedation results from central H1 blockade. Combined with pyridoxine (vitamin B6) it enhances antiemetic action via several pathways: H1 blockade reduces vomiting centre activity and pyridoxine participates in synthesis of neurotransmitters regulating emesis. Half-life 10–12 hours, so morning drowsiness is common.

Indications

Nausea and vomiting in pregnancy

First line

Doxylamine 10 mg + pyridoxine 10 mg (Cariban in Spain) is first-line therapy for moderate nausea and vomiting in pregnancy. AEMPS authorises it from the first trimester; 2018 and SEGO 2023 position it on the first step after pyridoxine monotherapy. Safety is supported by 70 years of clinical experience (since 1956); meta-analyses of more than 200,000 pregnancies show no teratogenicity. Dosing: 1-2 capsules at bedtime, adding morning and afternoon doses if symptoms persist. The main adverse effect is drowsiness, so therapy starts with the evening dose.

Doxylamine

Mechanism of action

Indications

Nausea and vomiting in pregnancy

Marketing claims without evidence base

Insomnia and sleep disorders

Check interaction with another drug

Official sources

Safety

Contraindications

Serious adverse effects

Common adverse effects

PregnancyFDA A

Breastfeeding

Frequently asked