Phentermine and topiramate and Selegiline interaction
Phentermine and topiramate and Selegiline: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
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 and topiramate label · effective 2026-05-18
…Warnings and Precautions (5.1) and Use in Specific Populations (8.1) ] With glaucoma [see Warnings and Precautions (5.3) ] With hyperthyroidism Taking or within 14 days of stopping a monoamine oxidase inhibitors [see Drug Interactions (7) ] With known hypersensitivity to phentermine, topiramate or any of the excipients in phentermine and topiramate extended-release…
Taking or within 14 days of stopping monoamine oxidase inhibitors ( 4 )
Intervention Concomitant use of phentermine and topiramate extended-release capsules are contraindicated during MAOI treatment and within 14 days of stopping an MAOI.
Clinically Significant Drug Interactions with Phentermine and Topiramate Extended-Release Capsules Monoamine Oxidase Inhibitors Clinical Impact Concomitant use of phentermine with monoamine oxidase inhibitors (MAOIs) increases the risk of hypertensive crisis.
From the Selegiline (ZELAPAR) label · effective 2021-06-01
Uncontrolled hypertension has been reported when taking the recommended dose of swallowed selegiline and a sympathomimetic medication (ephedrine).
Sympathomimetic Medications Uncontrolled hypertension, including hypertensive crisis, has been reported when taking the recommended dose of swallowed selegiline and a sympathomimetic medication (ephedrine).
Drugs that induce CYP3A4 (e.g., phenytoin, carbamazepine, nafcillin, phenobarbital, and rifampin) should be used with caution.
Drugs that Induce CYP450 Adequate studies have not been done investigating the effect of CYP3A4 inducers on selegiline.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot 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.