Haloperidol and Trihexyphenidyl interaction
Haloperidol and Trihexyphenidyl: 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 Trihexyphenidyl (Trihexyphenidyl Hydrochloride) label · effective 2025-07-02
Neuroleptic Malignant Syndrome A potentially fatal symptom complex sometimes referred to as Neuroleptic Malignant Syndrome (NMS) has been reported in association with dose reduction or Discontinuation of trihexyphenidyl.
Prophylactic administration of anticholinergic agents, such as trihexyphenidyl, as a prevention of drug-induced parkinsonism during neuroleptic therapy is not recommended.
Concurrent use of alcohol or other CNS depressants with trihexyphenidyl HCl may cause increased sedative effects.
There may be an increased risk for the development of tardive dyskinesia during concomitant administration of anticholinergics and neuroleptics ( see PRECAUTIONS , General ).
From the Haloperidol (Haldol Decanoate) label · effective 2025-11-11
Anticholinergic Drugs Clinical Impact The healthcare provider should keep in mind the possible increase in intraocular pressure when anticholinergic drugs are administered concomitantly with HALDOL DECANOATE.
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.