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Trihexyphenidyl (Benzhexol)

    DEA Class;  Rx

    Common Brand Names; Artane, Trihex

    • Antiparkinson Agents, Anticholinergics

    An oral synthetic, tertiary antimuscarinic that penetrates the central nervous system (CNS)
    Indicated as an adjunct in the treatment of all forms of parkinsonism (postencephalitic, arteriosclerotic, and idiopathic); often useful as adjuvant therapy with levodopa
    Also helps control of extrapyramidal disorders due to CNS drugs (e.g., phenothiazines, thioxanthenes, and butyrophenones)

    Indicated for the treatment of idiopathic parkinsonism or Parkinson’s disease.

    For the treatment of drug-induced extrapyramidal symptoms

    For the treatment of clozapine-induced sialorrhea† (drooling).


    Angle-closure glaucoma

    • Anticholinergic side effects (30-50%)
    • Rash
    • Suppurative parotitis
    • Hallucination
    • Paralytic ileus

    Exacerbation of parkinsonism, neuroleptic malignant syndrome, and withdrawal symptoms associated with therapy discontinuation or dose reduction; drug should be withdrawn gradually

    Perform gonioscope evaluation before initiating treatment; monitor intraocular pressure closely at regular periodic intervals

    Therapy may impair memory and exacerbate cognitive deficits in the elderly; may also cause delirium, hallucinations, and confusion when administered at high doses

    Use extreme caution and monitor closely patients with liver, cardiac, kidney disorders, prostatic hyperplasia (urinary stricture), or with hypertension

    Pregnancy Category: C

    Lactation: no data; may inhibit lactation


    15 mg/day PO.


    15 mg/day PO.


    Safety and efficacy have not been established.


    Safety and efficacy have not been established.

    Trihexyphenidyl hydrochloride 


    • 2mg
    • 5mg


    • 0.4mg/mL