Drug interactions
Fentanyl + Loperamide
Severity: Major
Fentanyl and Loperamide: 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
Both are opioids, and loperamide at high doses or with increased absorption can add central effects, while both may prolong QT. Combined use may increase sedation, respiratory depression and arrhythmia risk.
What this interaction means in plain words
Fentanyl and Loperamide 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.
Fentanyl belongs to Musculoskeletal; Loperamide belongs to Gastrointestinal Tract.
Why it happens
Additive opioid-mediated CNS and respiratory depression, with possible additive QT prolongation.
What to do
Keep loperamide at labeled doses and monitor sedation and respiratory rate. Avoid additional CNS depressants and check ECG in patients with QT risk factors.
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 Loperamide
Other interactions of Fentanyl
- Alvimopan + Fentanyl Contraindicated
- Fentanyl + Isocarboxazid Contraindicated
- Fentanyl + Olanzapine / samidorphan Contraindicated
- Fentanyl + Phenelzine Contraindicated
- Fentanyl + Tranylcypromine Contraindicated
- Alfentanil + Fentanyl Major
Frequently asked questions
Can I take Fentanyl with Loperamide?
MediHelp rates the interaction as major. Fentanyl and Loperamide 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. Both are opioids, and loperamide at high doses or with increased absorption can add central effects, while both may prolong QT. Combined use may increase sedation, respiratory depression and arrhythmia risk.
How serious is the interaction between Fentanyl and Loperamide?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Keep loperamide at labeled doses and monitor sedation and respiratory rate. Avoid additional CNS depressants and check ECG in patients with QT risk factors.
What other medicines interact with Loperamide?
MediHelp also lists interactions of Loperamide with, for example, Amiodarone, Amisulpride, Anagrelide. The full list is on the Loperamide page.
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