Dextromethorphan and Phenelzine: Drug Interaction Guide
Quick answer: This is a major interaction — avoid combining Dextromethorphan and Phenelzine unless specifically directed by your doctor.
How Dextromethorphan interacts with Phenelzine
Dextromethorphan inhibits serotonin reuptake, while irreversible monoamine oxidase inhibition by phenelzine prevents serotonin metabolism, creating a high risk of serotonin syndrome.
What you should do
Do not combine. Avoid dextromethorphan during phenelzine treatment and for at least 14 days after phenelzine discontinuation.
Key facts
Severity
Major — avoid combination
Mechanism
Dextromethorphan inhibits serotonin reuptake, while irreversible monoamine oxidase inhibition by phenelzine prevents ser...
Action
Do not combine. Avoid dextromethorphan during phenelzine treatment and for at least 14 days after phenelzine discontinua...
Frequently asked questions
Can I take Dextromethorphan and Phenelzine together?
No — this combination should generally be avoided. Do not combine. Avoid dextromethorphan during phenelzine treatment and for at least 14 days after phenelzine discontinuation.
What is the severity of this interaction?
The interaction between Dextromethorphan and Phenelzine is classified as Major — avoid combination. Dextromethorphan inhibits serotonin reuptake, while irreversible monoamine oxidase inhibition by phenelzine prevents serotonin metabolism, creating a high risk of serotonin syndrome.
What should I do if I'm prescribed both?
Do not combine. Avoid dextromethorphan during phenelzine treatment and for at least 14 days after phenelzine discontinuation. Always consult your prescribing clinician — do not stop or change medications without medical guidance.
Last reviewed: by iMedic Medical Editorial Team. Our editorial process.