Skip to content

Drug interactions

Dimenhydrinate + Fentanyl

Severity: Moderate

Dimenhydrinate and Fentanyl: 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

Dimenhydrinate is a sedating, anticholinergic antihistamine and adds to the CNS depression of fentanyl. Combined anticholinergic and opioid effects may worsen constipation and urinary retention.

What this interaction means in plain words

Dimenhydrinate and Fentanyl 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.

Dimenhydrinate belongs to Respiratory; Fentanyl belongs to Musculoskeletal.

Evidence level: Moderate

Why it happens

Additive CNS depression and anticholinergic effects.

What to do

Monitor sedation and respiratory status and ask about constipation and urinary retention. Use an alternative antiemetic if sedation is problematic.

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?

Bring a full list of your medicines, including over-the-counter products, supplements and herbal remedies, to every pharmacy visit.

Pro+ members

Unlock the full page

Create an account and start a Pro+ trial to unlock the full management advice for Dimenhydrinate and Fentanyl, 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.

Frequently asked questions

Can I take Dimenhydrinate with Fentanyl?

MediHelp rates the interaction as moderate. Dimenhydrinate and Fentanyl 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. Dimenhydrinate is a sedating, anticholinergic antihistamine and adds to the CNS depression of fentanyl. Combined anticholinergic and opioid effects may worsen constipation and urinary retention.

How serious is the interaction between Dimenhydrinate and Fentanyl?

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 sedation and respiratory status and ask about constipation and urinary retention. Use an alternative antiemetic if sedation is problematic.

What other medicines interact with Fentanyl?

MediHelp also lists interactions of Fentanyl with, for example, Alvimopan, Isocarboxazid, Olanzapine / samidorphan. The full list is on the Fentanyl 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.

Browse A–Z · Drug interactions

Get the app Sign in