Doxylamine: Uses, Dosage, Side Effects and More

Generic Medicine Info Patient Medicine Information

This information is not country-specific. Please refer to the Malaysia prescribing information.

Generic Medicine Info

Indications and Dosage

Oral
Short-term management of insomnia

Adult: 25 mg once daily, given 30 minutes before bedtime. Use for the shortest possible duration.
Child: ≥12 years Same as adult dose.

Administration

Doxylamine Should be taken with food.

Special Precautions

Patient with breathing problems (e.g. chronic bronchitis, emphysema), glaucoma, prostate enlargement, urinary retention, pyloroduodenal obstruction, epilepsy, severe CV disorders. Children (not recommended for <12 years). Pregnancy and lactation.

Adverse Reactions

Significant: CNS depression.
Cardiac disorders: Palpitations, tachycardia.
Ear and labyrinth disorders: Vertigo.
Eye disorders: Diplopia, blurred vision.
Gastrointestinal disorders: Diarrhoea, constipation, epigastric pain, xerostomia.
Metabolism and nutrition disorders: Anorexia.
Nervous system disorders: Dizziness, drowsiness, headache.
Psychiatric disorders: Disorientation, insomnia, nervousness, euphoria, irritability, nightmares, hallucinations.
Renal and urinary disorders: Dysuria, urinary retention.

Pregnancy Category (US FDA)

PO: B (FDA Pregnancy Category A applies to doxylamine succinate w/ pyridoxine hydrochloride.)

Patient Counseling Information

This drug may cause drowsiness, if affected, do not drive or operate machinery.

Overdosage

Symptoms: Dry mouth, fixed and dilated pupils, flushing, gastrointestinal symptoms, insomnia, nervousness, euphoria, irritability, tremors, nightmares, hallucination, pyschosis, CNS depression or stimulation, impaired consciousness, tachycardia, rhabdomyolysis with renal impairment and acute renal failure; coma, grand mal seizures, cardiorespiratory arrest. Management: Symptomatic and supportive treatment. Monitor vital signs for any abnormality. Ensure adequate ventilation by providing full supportive care, including oxygen and assisted ventilation. Provide adequate fluid replacement and maintain good urine output. Perform gastric lavage or administer activated charcoal within 60 minutes after ingestion. Consider whole bowel irrigation with polyethylene glycol electrolyte lavage solution for extremely large ingestion.

Drug Interactions

May enhance the CNS depressant effect with other CNS depressants such as opioid analgesics, neuroleptics, hypnotics, and psychotherapeutic drugs. May increase anticholinergic effect with MAOIs. Additive antimuscarinic effects with other antimuscarinic drugs (e.g. atropine, TCAs). May reduce the emetic response to apomorphine.

Food Interaction

May enhance the CNS depressant effect with alcohol.

Lab Interference

May suppress positive skin test results in dermal reactivity indicators. May cause false-positive reaction in urine detection of methadone.

Action

Description:
Mechanism of Action: Doxylamine is a monoethanolamine derivative antihistamine that has sedative, hypnotic, anticholinergic, and antimuscarinic properties. It competes with histamine for H₁-receptor sites on effector cells, blocks the chemoreceptor trigger zone, reduces vestibular stimulation, and depresses labyrinthine function.
Duration: 6-8 hours.
Pharmacokinetics:
Absorption: Easily absorbed from the gastrointestinal tract. Time to peak plasma concentration: 2-4 hours.
Distribution: Enters breast milk. Volume of distribution: 2.5 L/kg.
Metabolism: Metabolised in the liver via N-dealkylation into metabolites.
Excretion: Via urine (60% as unchanged drug; metabolites). Elimination half-life: 10-12 hours.

Chemical Structure

Storage

Store between 20-25°C.

MIMS Class

Hypnotics & Sedatives

ATC Classification

R06AA09 - doxylamine ; Belongs to the class of aminoalkyl ethers used as systemic antihistamines.

References

Basic Care Sleep Aid Tablet (Amazon.com Services LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 16/07/2025.

Brayfield A, Cadart C (eds). Doxylamine Succinate. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 16/07/2025.

Doxylamine Succinate. UpToDate Lexidrug, AHFS DI (Adult and Pediatric) Online. American Society of Health-System Pharmacists, Inc. Waltham, MA. UpToDate, Inc. https://online.lexi.com. Accessed 16/07/2025.

Doxylamine. UpToDate Lexidrug, Lexi-Drugs Multinational Online. Waltham, MA. UpToDate, Inc. https://online.lexi.com. Accessed 16/07/2025.

Wilson Consumer Products. Dozile 25 mg Capsules data sheet 13 May 2019. Medsafe. http://www.medsafe.govt.nz. Accessed 16/07/2025.

Disclaimer: This information is independently developed by MIMS based on Doxylamine from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2025 MIMS. All rights reserved. Powered by MIMS.com