Drug interactions
Diphenhydramine + Gabapentin
Severity: Moderate
Diphenhydramine and Gabapentin: 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 and gabapentin both depress the CNS. Together they can cause pronounced sedation, confusion and falls, and respiratory depression in susceptible patients.
What this interaction means in plain words
Diphenhydramine and Gabapentin 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; Gabapentin belongs to Central Nervous System.
Why it happens
Additive pharmacodynamic CNS depression.
What to do
Use the lowest effective doses and avoid alcohol and driving. Monitor for oversedation and respiratory depression, and avoid diphenhydramine in older adults where 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 Gabapentin
Other interactions of Diphenhydramine
Frequently asked questions
Can I take Diphenhydramine with Gabapentin?
MediHelp rates the interaction as moderate. Diphenhydramine and Gabapentin 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 and gabapentin both depress the CNS. Together they can cause pronounced sedation, confusion and falls, and respiratory depression in susceptible patients.
How serious is the interaction between Diphenhydramine and Gabapentin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use the lowest effective doses and avoid alcohol and driving. Monitor for oversedation and respiratory depression, and avoid diphenhydramine in older adults where possible.
What other medicines interact with Gabapentin?
MediHelp also lists interactions of Gabapentin with, for example, Alprazolam, Amobarbital, Belladonna and opium. The full list is on the Gabapentin page.
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