Drug interactions
Diphenhydramine + Topiramate
Severity: Minor
Diphenhydramine and Topiramate: minor 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 markedly sedating, and with topiramate it can increase drowsiness and cognitive impairment. Older adults are at higher risk of confusion and falls.
What this interaction means in plain words
Diphenhydramine and Topiramate have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Diphenhydramine belongs to Respiratory; Topiramate belongs to Central Nervous System.
Why it happens
Additive CNS depressant effects of topiramate and diphenhydramine.
What to do
Advise the patient about additive sedation and avoid driving until response is known. Avoid diphenhydramine in older patients on topiramate where possible.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Topiramate
Other interactions of Diphenhydramine
Frequently asked questions
Can I take Diphenhydramine with Topiramate?
MediHelp rates the interaction as minor. Diphenhydramine and Topiramate have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Diphenhydramine is markedly sedating, and with topiramate it can increase drowsiness and cognitive impairment. Older adults are at higher risk of confusion and falls.
How serious is the interaction between Diphenhydramine and Topiramate?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Advise the patient about additive sedation and avoid driving until response is known. Avoid diphenhydramine in older patients on topiramate where possible.
What other medicines interact with Topiramate?
MediHelp also lists interactions of Topiramate with, for example, Benzhydrocodone / acetaminophen, Buprenorphine long-acting, Buprenorphine subdermal implant. The full list is on the Topiramate page.
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