Drug interactions
Belladonna and opium + Phenelzine
Severity: Major
Belladonna and opium and Phenelzine: 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
The opium component can cause serotonin syndrome or severe opioid toxicity with an MAOI, and belladonna adds anticholinergic effects. Respiratory depression, hypotension and hyperthermia are of concern.
What this interaction means in plain words
Belladonna and opium and Phenelzine 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
Probable additive CNS depression and serotonergic effects from opium alkaloids; mechanism not firmly established.
What to do
Avoid during phenelzine therapy and for 14 days after stopping it; select a non-opioid alternative. If unavoidable, use minimal doses with close monitoring of vital signs and mental status.
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 Phenelzine
- 5-HTP + Phenelzine Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amoxapine + Phenelzine Contraindicated
- Atomoxetine + Phenelzine Contraindicated
- Benzphetamine + Phenelzine Contraindicated
- Brimonidine + Phenelzine Contraindicated
Frequently asked questions
Can I take Belladonna and opium with Phenelzine?
MediHelp rates the interaction as major. Belladonna and opium and Phenelzine 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. The opium component can cause serotonin syndrome or severe opioid toxicity with an MAOI, and belladonna adds anticholinergic effects. Respiratory depression, hypotension and hyperthermia are of concern.
How serious is the interaction between Belladonna and opium and Phenelzine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid during phenelzine therapy and for 14 days after stopping it; select a non-opioid alternative. If unavoidable, use minimal doses with close monitoring of vital signs and mental status.
What other medicines interact with Phenelzine?
MediHelp also lists interactions of Phenelzine with, for example, 5-HTP, Amitriptyline, Amoxapine. The full list is on the Phenelzine page.
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