Brompheniramine, pseudoephedrine, and dextromethorphan and Phentermine and topiramate interaction
Brompheniramine, pseudoephedrine, and dextromethorphan and Phentermine and topiramate: 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
…(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 capsules, or idiosyncrasy to the sympathomimetic amines.
Known hypersensitivity to any component of phentermine and topiramate extended-release capsules or idiosyncrasy to sympathomimetic amines ( 4 )
From the Brompheniramine, pseudoephedrine, and dextromethorphan (Brompheniramine Maleate, Pseudoephedrine Hydrochloride and Dextromethorphan Hydrobromide) label · effective 2026-01-13
Central Nervous System (CNS) depressants Antihistamines have additive effects with alcohol and other CNS depressants (hypnotics, sedatives, tranquilizers, antianxiety agents, etc.). Antihypertensive drugs Sympathomimetic may reduce the effects of antihypertensive drugs.
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.