Drug interactions
Diphenhydramine + Melatonin
Severity: Minor
Diphenhydramine and Melatonin: minor interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Diphenhydramine is a strongly sedating antihistamine often used as a sleep aid, and melatonin also causes drowsiness. Together they may increase somnolence and next-day impairment, particularly in older adults.
What this interaction means in plain words
Diphenhydramine and Melatonin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Diphenhydramine belongs to Respiratory; Melatonin belongs to Gastrointestinal Tract.
Why it happens
Additive central nervous system depressant effects.
What to do
Avoid taking both for sleep where possible, and advise against driving until response is known. Avoid alcohol and other sedatives.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Melatonin
- Fluvoxamine + Melatonin Major
- Alfentanil + Melatonin Moderate
- Belladonna and opium + Melatonin Moderate
- Buprenorphine buccal + Melatonin Moderate
- Butabarbital + Melatonin Moderate
- Butalbital + Melatonin Moderate
Other interactions of Diphenhydramine
Frequently asked questions
Can I take Diphenhydramine with Melatonin?
MediHelp rates the interaction as minor. Diphenhydramine and Melatonin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Diphenhydramine is a strongly sedating antihistamine often used as a sleep aid, and melatonin also causes drowsiness. Together they may increase somnolence and next-day impairment, particularly in older adults.
How serious is the interaction between Diphenhydramine and Melatonin?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid taking both for sleep where possible, and advise against driving until response is known. Avoid alcohol and other sedatives.
What other medicines interact with Melatonin?
MediHelp also lists interactions of Melatonin with, for example, Fluvoxamine, Alfentanil, Belladonna and opium. The full list is on the Melatonin page.
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