Drug interactions
Diphenhydramine + Maprotiline
Severity: Moderate
Diphenhydramine and Maprotiline: 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
Both drugs are sedating and strongly anticholinergic, so combined use can cause marked drowsiness and impaired psychomotor function. Anticholinergic toxicity, including confusion, urinary retention, constipation, tachycardia and blurred vision, may occur especially in older patients. Diphenhydramine may also inhibit CYP2D6, which can raise maprotiline levels.
What this interaction means in plain words
Diphenhydramine and Maprotiline 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; Maprotiline belongs to Central Nervous System.
Why it happens
Additive antihistaminic and antimuscarinic effects, with possible CYP2D6 inhibition by diphenhydramine increasing maprotiline exposure.
What to do
Avoid combining where possible, particularly in older adults, and use a non-sedating antihistamine instead. If used together, counsel about driving and monitor for anticholinergic effects.
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 Maprotiline
- Arsenic trioxide + Maprotiline Contraindicated
- Disopyramide + Maprotiline Contraindicated
- Dofetilide + Maprotiline Contraindicated
- Ibutilide + Maprotiline Contraindicated
- Isocarboxazid + Maprotiline Contraindicated
- Maprotiline + Methylene blue Contraindicated
Other interactions of Diphenhydramine
Frequently asked questions
Can I take Diphenhydramine with Maprotiline?
MediHelp rates the interaction as moderate. Diphenhydramine and Maprotiline 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. Both drugs are sedating and strongly anticholinergic, so combined use can cause marked drowsiness and impaired psychomotor function. Anticholinergic toxicity, including confusion, urinary retention, constipation, tachycardia and blurred vision, may occur especially in older patients. Diphenhydramine may also inhibit CYP2D6, which can raise maprotiline levels.
How serious is the interaction between Diphenhydramine and Maprotiline?
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 combining where possible, particularly in older adults, and use a non-sedating antihistamine instead. If used together, counsel about driving and monitor for anticholinergic effects.
What other medicines interact with Maprotiline?
MediHelp also lists interactions of Maprotiline with, for example, Arsenic trioxide, Disopyramide, Dofetilide. The full list is on the Maprotiline page.
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