Drug interactions
Cyproheptadine + Fentanyl
Severity: Moderate
Cyproheptadine 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
Both drugs depress the CNS, so together they can cause greater drowsiness, impaired psychomotor function and respiratory depression. Cyproheptadine's anticholinergic activity may also add to opioid-related constipation and urinary retention.
What this interaction means in plain words
Cyproheptadine 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.
Cyproheptadine belongs to Respiratory; Fentanyl belongs to Musculoskeletal.
Why it happens
Additive CNS depression from opioid agonism and antihistamine sedation, plus additive anticholinergic effects on gut and bladder.
What to do
Use the lowest effective doses and monitor sedation and respiratory rate, especially after dose increases. Monitor bowel and bladder function and counsel patients to avoid driving or alcohol.
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 Cyproheptadine
- Cyproheptadine + Isocarboxazid Contraindicated
- Cyproheptadine + Phenelzine Contraindicated
- Cyproheptadine + Tranylcypromine Contraindicated
- Alfentanil + Cyproheptadine Major
- Belladonna and opium + Cyproheptadine Major
- Benzhydrocodone / acetaminophen + Cyproheptadine Major
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 Cyproheptadine with Fentanyl?
MediHelp rates the interaction as moderate. Cyproheptadine 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. Both drugs depress the CNS, so together they can cause greater drowsiness, impaired psychomotor function and respiratory depression. Cyproheptadine's anticholinergic activity may also add to opioid-related constipation and urinary retention.
How serious is the interaction between Cyproheptadine 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: Use the lowest effective doses and monitor sedation and respiratory rate, especially after dose increases. Monitor bowel and bladder function and counsel patients to avoid driving or alcohol.
What other medicines interact with Cyproheptadine?
MediHelp also lists interactions of Cyproheptadine with, for example, Isocarboxazid, Phenelzine, Tranylcypromine. The full list is on the Cyproheptadine page.
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