Brompheniramine, pseudoephedrine, and dextromethorphan and Phentermine interaction
Brompheniramine, pseudoephedrine, and dextromethorphan and Phentermine: 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 (Phentermine hydrochloride) label · effective 2026-08-17
…states • History of drug abuse • Pregnancy [ see Use in Specific Populations () ] • Nursing [ see Use in Specific Populations ( 8.3 ) ] • Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines • History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) () • During or within…
• Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines ( 4 )
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.
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.