Drug interactions
Diphenhydramine + Metaxalone
Severity: Moderate
Diphenhydramine and Metaxalone: 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 first-generation antihistamine and may add to the drowsiness and dizziness caused by metaxalone. Psychomotor impairment and fall risk can increase, especially in elderly patients.
What this interaction means in plain words
Diphenhydramine and Metaxalone 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; Metaxalone belongs to Musculoskeletal.
Why it happens
Additive central nervous system depression through pharmacodynamic synergy.
What to do
Warn the patient about additive sedation and avoid driving until tolerance is known. Consider a non-sedating antihistamine, particularly in older adults.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Diphenhydramine and Metaxalone, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Metaxalone
Other interactions of Diphenhydramine
Frequently asked questions
Can I take Diphenhydramine with Metaxalone?
MediHelp rates the interaction as moderate. Diphenhydramine and Metaxalone 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 first-generation antihistamine and may add to the drowsiness and dizziness caused by metaxalone. Psychomotor impairment and fall risk can increase, especially in elderly patients.
How serious is the interaction between Diphenhydramine and Metaxalone?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Warn the patient about additive sedation and avoid driving until tolerance is known. Consider a non-sedating antihistamine, particularly in older adults.
What other medicines interact with Metaxalone?
MediHelp also lists interactions of Metaxalone with, for example, Alfentanil, Belladonna and opium, Benzhydrocodone / acetaminophen. The full list is on the Metaxalone page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
