Trihexyphenidyl is an anticholinergic medication that is primarily used to treat the symptoms of Parkinson's disease and drug-induced extrapyramidal disorders caused by antipsychotic medications. It works by blocking central muscarinic receptors, thereby restoring the balance between dopamine and acetylcholine in the brain and reducing tremors, muscle rigidity, and excessive salivation. Trihexyphenidyl was first synthesized in the 1940s and introduced into clinical practice in 1949, becoming one of the earliest orally effective anticholinergic agents for the management of Parkinsonism. Although its use has declined with the availability of newer antiparkinsonian drugs, it remains an important therapeutic option, particularly for younger patients with tremor-predominant Parkinson's disease and for the treatment of medication-induced movement disorders.
