Amitriptyline and Phentermine and topiramate interaction
Amitriptyline and Phentermine and topiramate: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Amitriptyline (Amitriptyline Hydrochloride) label · effective 2025-11-25
Drug Interactions Topiramate Some patients may experience a large increase in amitriptyline concentration in the presence of topiramate and any adjustments in amitriptyline dose should be made according to the patient's clinical response and not on the basis of plasma levels.
When amitriptyline is given with anticholinergic agents or sympathomimetic drugs, including epinephrine combined with local anesthetics, close supervision and careful adjustment of dosages are required.
Guanethidine or similarly acting compounds; thyroid medication; alcohol, barbiturates and other CNS depressants; and disulfiram – see WARNINGS section.
From the Phentermine and topiramate label · effective 2026-05-18
Amitriptyline Clinical Impact Some patients may experience a large increase in amitriptyline concentration in the presence of topiramate.
Intervention Any adjustments in amitriptyline dose when used with phentermine and topiramate extended-release capsules should be made according to the patient's clinical response and not on the basis of amitriptyline levels [see Clinical Pharmacology (12.3) ] .
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.