Phentermine and Tranylcypromine interaction

Phentermine and Tranylcypromine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.

Major

Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.

What the FDA labels say

From the Phentermine (Phentermine hydrochloride) label · effective 2026-08-17

Major

…cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) • During or within 14 days following the administration of monoamine oxidase inhibitors • Hyperthyroidism • Glaucoma • Agitated states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific…

Contraindicationsby drug classView label on DailyMed
Major

Monoamine Oxidase Inhibitors Use of phentermine is contraindicated during or within 14 days following the administration of monoamine oxidase inhibitors because of the risk of hypertensive crisis.

Drug interactionsby drug classView label on DailyMed
Moderate

Monoamine oxidase inhibitors: Risk of hypertensive crisis.

Drug interactionsby drug classView label on DailyMed
Minor

The safety and efficacy of combination therapy with phentermine and any other drug products for weight loss including prescribed drugs, over-the-counter preparations, and herbal products, or serotonergic agents such as selective serotonin reuptake inhibitors (e.g., fluoxetine, sertraline, fluvoxamine, paroxetine), have not been established.

Warnings and precautionsby drug classView label on DailyMed

From the Tranylcypromine (Tranylcypromine Sulfate) label · effective 2025-07-25

Major

…(SSRIs) and serotonin and norepinephrine reuptake inhibitors (SNRIs) tricyclic antidepressants other antidepressants, such as amoxapine, bupropion, maprotiline, nefazodone, trazodone, vilazodone, vortioxetine amphetamines and methylphenidates medicines that can raise blood pressure (sympathomimetic medicine), such as pseudoephedrine, phenylephrine and ephedrine.

Boxed warningby drug classView label on DailyMed
Major

These medicines are in some cold, hay fever or weight-loss medicines. sympathomimetic herbal medicines or dietary supplements antihistamines (allergy medicines) triptans buspirone carbamazepine dextromethorphan dopamine hydroxytryptophan and tryptophan levodopa and methyldopa meperidine rasagline resperine s-adenosyl-L-methionine (SAM-e) tapentadol tetrabenazin…

Boxed warningby drug classView label on DailyMed
Major

Concomitant use or use in rapid succession with other MAOIs; selective serotonin reuptake inhibitors; serotonin and norepinephrine reuptake inhibitors; tricyclic antidepressants; sympathomimetic drugs; and numerous other drugs.

Contraindicationsby drug classView label on DailyMed
Major

…antidepressants Other antidepressants (e.g., amoxapine, bupropion, maprotiline, nefazodone, trazodone, vilazodone, vortioxetine) Amphetamines and methylphenidates and derivatives Sympathomimetic products (e.g., cold, hay fever or weight reducing products that contain vasoconstrictors such as pseudoephedrine, phenylephrine, and ephedrine; or dietary supplements…

Contraindicationsby drug classView label on DailyMed
Major

…Contraindicated Drugs If in the absence of therapeutic alternatives emergency treatment with a contraindicated product (e.g., linezolid, intravenous methylene blue, direct-acting sympathomimetic drugs such as epinephrine) becomes necessary and cannot be delayed, discontinue tranylcypromine sulfate tablets as soon as possible before initiating treatment with…

Warnings and precautionsby drug classView label on DailyMed

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Not medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.