Carbidopa and levodopa and Trihexyphenidyl interaction
Carbidopa and levodopa and Trihexyphenidyl: the Trihexyphenidyl prescribing label describes 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 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.