Drug interactions
Diphenoxylate + Phenelzine
Severity: Major
Diphenoxylate 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
Diphenoxylate is a pethidine-related opioid, and its use with an MAOI may precipitate hypertensive or hypotensive reactions, hyperthermia, excess sedation and CNS depression. Fatal reactions have been described with opioids in MAOI-treated patients.
What this interaction means in plain words
Diphenoxylate 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.
Diphenoxylate belongs to Gastrointestinal Tract; Phenelzine belongs to Central Nervous System.
Why it happens
Not fully established; probably serotonergic and exaggerated CNS-depressant effects of the opioid under MAO inhibition.
What to do
Avoid diphenoxylate during MAOI therapy and for 14 days after stopping phenelzine. Use a non-opioid antidiarrheal such as loperamide, with monitoring of blood pressure 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
Other interactions of Diphenoxylate
Frequently asked questions
Can I take Diphenoxylate with Phenelzine?
MediHelp rates the interaction as major. Diphenoxylate 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. Diphenoxylate is a pethidine-related opioid, and its use with an MAOI may precipitate hypertensive or hypotensive reactions, hyperthermia, excess sedation and CNS depression. Fatal reactions have been described with opioids in MAOI-treated patients.
How serious is the interaction between Diphenoxylate 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 diphenoxylate during MAOI therapy and for 14 days after stopping phenelzine. Use a non-opioid antidiarrheal such as loperamide, with monitoring of blood pressure 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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