Antihistamine (sedating)
Last reviewed July 2026
Who is this for?
Diphenhydramine is an antihistamine that works by blocking a natural substance called histamine in your body. It reduces allergic reactions, helps you sleep, and can calm coughing by acting on the brain's cough and sleep centers.
Blocks H1 histamine receptors in the central and peripheral nervous system, suppressing allergic symptoms and inflammatory responses; additionally crosses the blood-brain barrier to produce sedation through anticholinergic effects and depression of the central nervous system.
Available Over The Counter
Get this from any pharmacy or chemist: no prescription needed.
Is Diphenhydramine safe to take with another drug?
Check with multiple drugs →Explore this drug
If you miss a dose, take it as soon as you remember. But if it is almost time for your next dose, skip the missed one and continue as normal. Do not double up to make up for a missed dose.
This drug makes you very drowsy, so do not drive, ride an okada, or operate machinery after taking it. Buy only from reputable pharmacies, not from roadside sellers or open markets, as fake or expired versions are common. Do not use it as a regular sleeping pill for a long time without seeing a doctor.
Do not take with alcohol, as it will make the drowsiness much worse and can be dangerous. Avoid using with other drugs that make you sleepy such as diazepam (Valium) or tramadol. Be careful combining it with other cold or allergy medicines as they may contain the same or similar ingredients, leading to overdose.
Check your specific combination
Is it safe to take Diphenhydramine with your other drugs?
Diphenhydramine is not recommended during pregnancy or breastfeeding unless your doctor specifically says it is okay, as it can pass to the baby and cause side effects.
Store in a cool, dry place away from direct sunlight and heat, as Nigerian weather can be very hot, so avoid leaving it in your car or near a window. Keep the container tightly closed to protect from humidity. Always keep out of reach of children.
For information only: not medical advice. Always talk to a doctor or pharmacist before changing your medication.
Names this drug is sold under, especially in Nigerian and West African pharmacies
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Counterfeit Drug Warning
Fake drugs are a serious problem in Nigeria. Always buy from a registered pharmacy. If the packaging looks different from what is described above, do not use it.