Doxylamine
Doxylamine is a first-generation antihistamine used to treat allergic conditions such as hay fever, allergic rhinitis, and mild skin reactions. It is also commonly used as a short-term sleep aid due to its sedating properties. The medication works by blocking histamine H1 receptors, reducing allergic symptoms like sneezing, itching, and runny nose.
Doxylamine is an antihistamine used for allergies and as a sleep aid, working by blocking histamine receptors.
Key facts at a glance
- ATC
- R06AA09
- RxNorm
- 3498
- Generic
- Doxylamine
- Class
- atc-r06
- Brands
- Diclegis, Wal-Som (doxylamine), Bonjesta, Unisom, Nocto, Zzzquil Ultra, Aldex AN
- Availability
- otc
- Pregnancy
- A
- Lactation
- caution
- Half-life (h)
- 10
- Onset (min)
- 30
- Duration (h)
- 8
- Routes
- oral
- Forms
- tablet, delayed-release tablet, capsule, oral solution, chewable tablet
- Regions
- United States, Canada, United Kingdom, Australia, European Union, New Zealand
- Monitoring
- sedation, anticholinergic effects, cognitive impairment in elderly
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 25mg once daily
- Maximum
- consult physician
- Frequency
- at bedtime
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 12.5mg once daily
- Maximum
- consult physician
- Frequency
- at bedtime
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 12.5mg once daily
- Maximum
- consult physician
- Frequency
- at bedtime
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
9 groupspregnancy
first trimesterstandard dose when used for nausea/vomiting of pregnancy
doxylamine/pyridoxine combination (Diclegis) is FDA-approved for nausea/vomiting in pregnancy; avoid using as sleep aid in first trimester unless specifically indicated
standard prenatal care
Use with caution and monitor for adverse effects.
pregnancy
second third trimesterstandard dose
continue use for nausea/vomiting of pregnancy as needed; avoid as sleep aid unless benefits clearly outweigh risks
standard prenatal monitoring
Use with caution and monitor for adverse effects.
lactation
breastfeedingno specific adjustment
small amounts excreted in breast milk; monitor infant for excessive drowsiness
observe infant for sedation or irritability
Use with caution and monitor for adverse effects.
geriatric
elderly 65 yearsstart with lowest effective dose
use with caution due to anticholinergic effects; increased risk of falls, confusion, and cognitive impairment; consider alternative sleep aids
monitor for sedation, dizziness, cognitive changes, and fall risk
Use with caution and monitor for adverse effects.
pediatric_age
children under 12not recommended
do not use for pediatric insomnia; contraindicated in children with asthma, narrow-angle glaucoma, or urinary retention
not applicable
Use of this medication in this population requires careful consideration of risks and benefits.
renal_impairment
mild to moderateno adjustment needed
no dose adjustment required for mild to moderate renal impairment
standard monitoring
renal_impairment
severereduce dose or increase dosing interval
use with caution; consider dose reduction; monitor for extended sedation
monitor for prolonged sedative effects
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderateconsider reduced dose
metabolized by liver; use reduced initial dose and titrate carefully
monitor for increased sedation
Use with caution and monitor for adverse effects.
hepatic_impairment
severesignificant dose reduction recommended
use with caution; significant dose reduction required; avoid prolonged use
close monitoring for sedation and adverse effects
Use with caution and monitor for adverse effects.
Statistics and clinical data
Drug class
First-generation H1 antihistamine agent
Common uses
Therapeutic indications for doxylamine succinate
FDA pregnancy category approval
Diclegis (doxylamine/pyridoxine) approved 2013
Mechanism of action
Primary pharmacological mechanism
Treatment of seasonal and perennial allergic rhinitis, allergic conjunctivitis, urticaria (hives), and dermatographism. Also used as a sedative-hypnotic for short-term insomnia and occasionally for nausea and vomiting in early pregnancy.
Doxylamine is a competitive H1 receptor antagonist that blocks histamine from binding to its receptors, preventing allergic symptoms. As a first-generation antihistamine, it readily crosses the blood-brain barrier and has anticholinergic properties, contributing to its sedating effect.
May cause significant drowsiness and impaired coordination; avoid driving or operating machinery. Should not be combined with alcohol or other CNS depressants. Contraindicated in patients with narrow-angle glaucoma, urinary retention, or severe respiratory disease. Use with caution in elderly patients due to increased sensitivity to anticholinergic effects and fall risk.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy