Drug interactions
Bretylium + Phenelzine
Severity: Major
Bretylium 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
Bretylium initially releases norepinephrine from sympathetic nerve terminals, and an MAO inhibitor blocks the breakdown of released and stored catecholamines. The combination may cause exaggerated pressor responses, tachycardia and arrhythmias. The effect is unpredictable and can be clinically significant in a patient with cardiac disease.
What this interaction means in plain words
Bretylium 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
Bretylium-induced catecholamine release is potentiated by MAO inhibition, which reduces catecholamine degradation.
What to do
Avoid the combination where possible; if bretylium is essential, monitor blood pressure, heart rate and ECG continuously. Be prepared to treat hypertensive episodes and arrhythmias.
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 Bretylium with Phenelzine?
MediHelp rates the interaction as major. Bretylium 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. Bretylium initially releases norepinephrine from sympathetic nerve terminals, and an MAO inhibitor blocks the breakdown of released and stored catecholamines. The combination may cause exaggerated pressor responses, tachycardia and arrhythmias. The effect is unpredictable and can be clinically significant in a patient with cardiac disease.
How serious is the interaction between Bretylium 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 the combination where possible; if bretylium is essential, monitor blood pressure, heart rate and ECG continuously. Be prepared to treat hypertensive episodes and arrhythmias.
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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