Isocarboxazid and Nortriptyline

Desk tier: Avoid together

Mechanism: MAOI × serotonergic (serotonin syndrome / hypertensive crisis)

“Marplan should not be administered together with, or in close proximity to, other MAO inhibitors or dibenzazepine-related entities … Nortriptyline HCL”

Marplan (isocarboxazid), section CONTRAINDICATIONS. DailyMed label

Why this grade

Marplan (isocarboxazid) label, Contraindications

The Marplan (isocarboxazid) label lists this combination under Contraindications. CONTRAINDICATIONS: "Marplan should not be administered together with, or in close proximity to, other MAO inhibitors or dibenzazepine-related entities … Nortriptyline HCL" Named in the label: "Nortriptyline HCL" Retrieved from DailyMed 2026-10-19.

Marplan (isocarboxazid) label on DailyMed

FDA boxed / safety communication

MAOI labels contraindicate serotonergic agents. Serotonin toxicity, hypertensive crisis.

Search DailyMed for Isocarboxazid

PMID 27997040

2017 Clin Pharmacol Ther. CPIC TCAs. Amitriptyline is 2D6 and 2C19.

PMID 27997040 on PubMed

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Educational reference only. Not FDA-cleared. The Prescribing Information governs.

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