Drug interactions
Difenoxin + Diphenhydramine
Severity: Moderate
Difenoxin and Diphenhydramine: 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
Difenoxin is an opioid antidiarrheal related to diphenoxylate, and it can cause sedation at higher doses. Diphenhydramine adds sedation, so drowsiness and impaired alertness may increase. Both drugs are anticholinergic in effect or in side effects, which can add to constipation and urinary retention.
What this interaction means in plain words
Difenoxin and Diphenhydramine 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.
Difenoxin belongs to Gastrointestinal Tract; Diphenhydramine belongs to Respiratory.
Why it happens
Additive central nervous system depression and additive anticholinergic effects.
What to do
Monitor for oversedation and reduced bowel motility. Keep to the lowest effective doses and counsel about driving.
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 Difenoxin
Frequently asked questions
Can I take Difenoxin with Diphenhydramine?
MediHelp rates the interaction as moderate. Difenoxin and Diphenhydramine 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. Difenoxin is an opioid antidiarrheal related to diphenoxylate, and it can cause sedation at higher doses. Diphenhydramine adds sedation, so drowsiness and impaired alertness may increase. Both drugs are anticholinergic in effect or in side effects, which can add to constipation and urinary retention.
How serious is the interaction between Difenoxin and Diphenhydramine?
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 oversedation and reduced bowel motility. Keep to the lowest effective doses and counsel about driving.
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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