Doxylamine is a sedating antihistamine used briefly for occasional insomnia in adults. It may shorten the time needed to fall asleep, but it does not treat the cause of sleep difficulties and is not a solution for chronic insomnia. It must not be used to make children sleep.
Take it by mouth in the evening, usually 15–30 minutes before bedtime, following the leaflet. Allow enough time for a full night's sleep. Do not exceed the dose or extend treatment without medical review. Avoid alcohol and do not combine it with opioids, sleeping pills, sedatives or other antihistamines without professional advice.
Possible effects include next-day drowsiness, dry mouth, constipation, blurred vision, palpitations and difficulty urinating. Older people have a greater risk of confusion and falls. Doxylamine can worsen sleep apnoea and is unsuitable in closed-angle glaucoma or conditions with a risk of urinary retention. Do not drive if alertness is impaired.
Seek urgent help for overdose, seizures, extreme sleepiness or severe confusion. If insomnia continues after a few days, consult a doctor rather than increasing the dose. Mention kidney or liver disease and all medicines you use. Ask for advice during pregnancy; use while breastfeeding is not recommended. Maintaining a regular sleep schedule remains important.