1 May 2026Oral drugs

Trihexyphenidyl Oral: Dosing and Safety

Trihexyphenidyl guidance for second-line treatment of antipsychotic-induced extrapyramidal reactions, with anticholinergic precautions.

Also searched as

Trihexyphenidyl

Prescription under medical supervision

Source reviewed

source date listed on the source page

Guide category

Oral drugs

Safety boundary

Prescription medicine information for clinician-guided use.

Kenza Health Hub presents this medicine page as structured health education. Check dose, route, interactions, pregnancy or breast-feeding considerations, and local protocol with a qualified clinician or pharmacist. Read our medical editorial policy.

This guide page is for structured reference only and does not replace a clinician, pharmacist, or emergency review. Dose choice, route choice, interactions, and safety decisions still need professional judgment.

Therapeutic action

Anticholinergic antiparkinson drug.

Indications

Second-line treatment of extrapyramidal reactions induced by antipsychotics.

Forms and strengths

2 mg tablet.

Dose

Adult: 2 mg once daily, then increase if necessary up to 2 mg 2 or 3 times daily, maximum 12 mg daily.
Administer the lowest effective dose in elderly patients and do not exceed 10 mg daily.

Duration

As long as antipsychotic treatment lasts.

Contra-indications, adverse effects, precautions

Do not administer to patients with closed-angle glaucoma, prostate disorders, gastrointestinal obstruction, or atony.
Administer with caution and carefully monitor use in elderly patients because of the risk of mental confusion and hallucinations.
May cause anticholinergic effects, confusion, hallucinations, and memory loss.
Avoid or monitor combination with other anticholinergic drugs such as atropine, amitriptyline, chlorpromazine, and promethazine.
Pregnancy: re-evaluate whether the antipsychotic treatment is still necessary. If treatment is continued, administer trihexyphenidyl at the lowest effective dose and observe the neonate if exposure occurred in the third trimester.
Breast-feeding: if treatment is necessary, administer at the lowest effective dose and observe the child for anticholinergic effects.
Take with meals.

Source

MSF Essential drugs practical guidelines (January 2026)

This page combines source-derived medicine reference sections with Kenza editorial context, while leaving out the Storage and Remarks sections from the source batch.

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