Drug interactions
Fentanyl transdermal + Morphine
Severity: Major
Fentanyl transdermal and Morphine: major 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
Using morphine with a fentanyl patch adds opioid effects, raising the risk of sedation, hypotension, respiratory depression and death. This pairing is often used deliberately for breakthrough pain in tolerant patients but still needs careful control.
What this interaction means in plain words
Fentanyl transdermal and Morphine 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 mu-opioid receptor agonism causing CNS and respiratory depression.
What to do
Use the lowest effective morphine doses for breakthrough pain, titrating cautiously. Monitor for sedation and respiratory depression, particularly during dose changes, and provide naloxone.
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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Other interactions of Morphine
- Alvimopan + Morphine Contraindicated
- Isocarboxazid + Morphine Contraindicated
- Morphine + Olanzapine / samidorphan Contraindicated
- Morphine + Phenelzine Contraindicated
- Morphine + Tranylcypromine Contraindicated
- Alfentanil + Morphine Major
Frequently asked questions
Can I take Fentanyl transdermal with Morphine?
MediHelp rates the interaction as major. Fentanyl transdermal and Morphine 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. Using morphine with a fentanyl patch adds opioid effects, raising the risk of sedation, hypotension, respiratory depression and death. This pairing is often used deliberately for breakthrough pain in tolerant patients but still needs careful control.
How serious is the interaction between Fentanyl transdermal and Morphine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use the lowest effective morphine doses for breakthrough pain, titrating cautiously. Monitor for sedation and respiratory depression, particularly during dose changes, and provide naloxone.
What other medicines interact with Morphine?
MediHelp also lists interactions of Morphine with, for example, Alvimopan, Isocarboxazid, Olanzapine / samidorphan. The full list is on the Morphine page.
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