Drug interactions
Diphenhydramine + Ramelteon
Severity: Moderate
Diphenhydramine and Ramelteon: moderate 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 that may add to ramelteon's hypnotic effect. This can lead to excessive sedation, confusion and falls, particularly in the elderly.
What this interaction means in plain words
Diphenhydramine and Ramelteon can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Diphenhydramine belongs to Respiratory; Ramelteon belongs to Central Nervous System.
Why it happens
Additive sedation from melatonin receptor agonism and central H1 antihistamine blockade.
What to do
Avoid using the two together as sleep aids and warn about next-day impairment. In older patients choose a single agent.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Ramelteon
- Calcium / magnesium / potassium / sodium oxybates + Ramelteon Contraindicated
- Fluvoxamine + Ramelteon Contraindicated
- Ramelteon + Sodium oxybate Contraindicated
- Alfentanil + Ramelteon Moderate
- Amitriptyline + Ramelteon Moderate
- Amobarbital + Ramelteon Moderate
Other interactions of Diphenhydramine
Frequently asked questions
Can I take Diphenhydramine with Ramelteon?
MediHelp rates the interaction as moderate. Diphenhydramine and Ramelteon can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Diphenhydramine is a strongly sedating antihistamine that may add to ramelteon's hypnotic effect. This can lead to excessive sedation, confusion and falls, particularly in the elderly.
How serious is the interaction between Diphenhydramine and Ramelteon?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid using the two together as sleep aids and warn about next-day impairment. In older patients choose a single agent.
What other medicines interact with Ramelteon?
MediHelp also lists interactions of Ramelteon with, for example, Calcium / magnesium / potassium / sodium oxybates, Fluvoxamine, Sodium oxybate. The full list is on the Ramelteon page.
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