Drug interactions
Cyproheptadine + Diamorphine
Severity: Major
Cyproheptadine and Diamorphine: 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
Diamorphine (heroin) is a potent opioid, and a sedating antihistamine can increase sedation and the risk of respiratory depression. Combined effects may be serious, especially at higher doses.
What this interaction means in plain words
Cyproheptadine and Diamorphine 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.
What to do
Use the lowest effective doses and monitor sedation and respiratory rate closely. Use a non-sedating antihistamine where an antihistamine is needed.
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 Cyproheptadine
- Cyproheptadine + Isocarboxazid Contraindicated
- Cyproheptadine + Phenelzine Contraindicated
- Cyproheptadine + Tranylcypromine Contraindicated
- Alfentanil + Cyproheptadine Major
- Belladonna and opium + Cyproheptadine Major
- Benzhydrocodone / acetaminophen + Cyproheptadine Major
Frequently asked questions
Can I take Cyproheptadine with Diamorphine?
MediHelp rates the interaction as major. Cyproheptadine and Diamorphine 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. Diamorphine (heroin) is a potent opioid, and a sedating antihistamine can increase sedation and the risk of respiratory depression. Combined effects may be serious, especially at higher doses.
How serious is the interaction between Cyproheptadine and Diamorphine?
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 doses and monitor sedation and respiratory rate closely. Use a non-sedating antihistamine where an antihistamine is needed.
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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