Amantadine and Trihexyphenidyl interaction
Amantadine and Trihexyphenidyl: 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 Amantadine (GOCOVRI) label · effective 2026-02-16
Other Anticholinergic Drugs: Doses should be reduced if atropine-like effects occur ( 7.1 )
Other Anticholinergic Drugs Products with anticholinergic properties may potentiate the anticholinergic-like side effects of amantadine.
From the Trihexyphenidyl (Trihexyphenidyl Hydrochloride) label · effective 2025-07-02
The usual dose of either trihexyphenidyl or levodopa may need to be reduced during concomitant therapy, since concomitant administration may increase drug-induced involuntary movements ( see DOSAGE AND ADMINISTRATION ).
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.