Trihexyphenidyl

Information about Trihexyphenidyl

Trihexyphenidyl is an oral anticholinergic agent used predominantly in the symptomatic therapy of Parkinson disease and movement disorders.  

Liver safety of Trihexyphenidyl

Trihexyphenidyl has not been associated with serum enzyme elevations during treatment, but has been implicated in rare cases of acute liver injury.  

Mechanism of action of Trihexyphenidyl

Trihexyphenidyl is an anticholinergic agent that blocks the central cholinergic receptors, helping to balance cholinergic transmission in the basal ganglia.  Trihexyphenidyl may also block dopamine reuptake and storage in central sites thus increasing dopaminergic activity.  The exact mechanism(s) by which the anticholinergic agents are beneficial for symptoms of Parkinson disease is unknown.  They are used largely in early Parkinsonism and as adjunctive therapy with levodopa or more potent antiParkinson disease agents.  Trihexyphenidyl was approved for use in the United States in 1949 and has been in use since.

Current indications include therapy of symptomatic Parkinson disease, as well as spastic disorders and extrapyramidal disorders due to medications. 

Dosage and administration for Trihexyphenidyl

Trihexyphenidyl is available in tablets of 2 and 5 mg, and as an elixir of 2 mg/5 mL in generic forms and formerly under the brand name Artane.  The recommended dose is 2 to 5 mg three times daily. 

Side effects of Trihexyphenidyl

Common side effects are due to its anticholinergic activity and include nervousness, confusion, drowsiness, tachycardia, blurred vision, constipation, dry mouth, nausea and urinary retention.

• Dailymed label info on Trihexyphenidyl
• FDA Trihexyphenidyl