Drug interactions
Diphenhydramine + Eliglustat
Severity: Moderate
Diphenhydramine and Eliglustat: 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 inhibits CYP2D6 and can raise eliglustat exposure, which prolongs PR, QRS and QT intervals at high concentrations. The risk is greatest in patients who also take CYP3A inhibitors or who are CYP2D6 poor metabolizers.
What this interaction means in plain words
Diphenhydramine and Eliglustat 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; Eliglustat belongs to Miscellaneous.
Why it happens
Diphenhydramine inhibits CYP2D6, reducing the metabolism of eliglustat.
What to do
Review for other CYP2D6 or CYP3A inhibitors and the patient's CYP2D6 genotype, and consider an alternative antihistamine. Monitor ECG if the combination is needed and adjust eliglustat dosing per labeling.
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
Other interactions of Eliglustat
- Amiodarone + Eliglustat Contraindicated
- Clarithromycin + Eliglustat Contraindicated
- Dronedarone + Eliglustat Contraindicated
- Eliglustat + Itraconazole Contraindicated
- Eliglustat + Ketoconazole Contraindicated
- Eliglustat + Pimozide Contraindicated
Frequently asked questions
Can I take Diphenhydramine with Eliglustat?
MediHelp rates the interaction as moderate. Diphenhydramine and Eliglustat 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 inhibits CYP2D6 and can raise eliglustat exposure, which prolongs PR, QRS and QT intervals at high concentrations. The risk is greatest in patients who also take CYP3A inhibitors or who are CYP2D6 poor metabolizers.
How serious is the interaction between Diphenhydramine and Eliglustat?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Review for other CYP2D6 or CYP3A inhibitors and the patient's CYP2D6 genotype, and consider an alternative antihistamine. Monitor ECG if the combination is needed and adjust eliglustat dosing per labeling.
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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