Drug interactions
Diphenhydramine + Lofepramine
Severity: Moderate
Diphenhydramine and Lofepramine: 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 have anticholinergic and sedative properties, so together they can cause marked dry mouth, urinary retention, constipation, confusion and drowsiness. Diphenhydramine may also inhibit CYP2D6 and modestly raise tricyclic exposure.
What this interaction means in plain words
Diphenhydramine and Lofepramine 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.
Why it happens
Additive anticholinergic and sedative effects, with CYP2D6 inhibition by diphenhydramine.
What to do
Monitor for anticholinergic and sedative adverse effects, particularly in older patients. Use a non-sedating antihistamine instead if possible.
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 Diphenhydramine
Frequently asked questions
Can I take Diphenhydramine with Lofepramine?
MediHelp rates the interaction as moderate. Diphenhydramine and Lofepramine 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 have anticholinergic and sedative properties, so together they can cause marked dry mouth, urinary retention, constipation, confusion and drowsiness. Diphenhydramine may also inhibit CYP2D6 and modestly raise tricyclic exposure.
How serious is the interaction between Diphenhydramine and Lofepramine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for anticholinergic and sedative adverse effects, particularly in older patients. Use a non-sedating antihistamine instead if possible.
What other medicines interact with Diphenhydramine?
MediHelp also lists interactions of Diphenhydramine with, for example, Alfentanil, Belladonna and opium, Benzhydrocodone / acetaminophen. The full list is on the Diphenhydramine page.
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