Drug interactions
Dimenhydrinate + Fentanyl transdermal
Severity: Major
Dimenhydrinate and Fentanyl transdermal: major interaction.
Last updated Sources: US FDA label
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 adds to the sedation and respiratory depression of fentanyl. Its anticholinergic effects can also worsen constipation and urinary retention, with a risk of paralytic ileus.
What this interaction means in plain words
Dimenhydrinate and Fentanyl transdermal can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Additive CNS and respiratory depression from opioid agonism plus H1-antihistamine sedation, with additive anticholinergic effects on gut and bladder.
What to do
Monitor sedation and respiratory rate, particularly in opioid-naive or older patients. Watch for urinary retention and constipation.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Dimenhydrinate
Frequently asked questions
Can I take Dimenhydrinate with Fentanyl transdermal?
MediHelp rates the interaction as major. Dimenhydrinate and Fentanyl transdermal can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Dimenhydrinate adds to the sedation and respiratory depression of fentanyl. Its anticholinergic effects can also worsen constipation and urinary retention, with a risk of paralytic ileus.
How serious is the interaction between Dimenhydrinate and Fentanyl transdermal?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor sedation and respiratory rate, particularly in opioid-naive or older patients. Watch for urinary retention and constipation.
What other medicines interact with Dimenhydrinate?
MediHelp also lists interactions of Dimenhydrinate with, for example, Belladonna and opium, Brexanolone, Calcium / magnesium / potassium / sodium oxybates. The full list is on the Dimenhydrinate page.
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