A medication with antispas-modic and anticholinergic properties taken to relieve symptoms of Parkinson’s such as tremors and rigidity as well as drug-induced neuromuscular side effects of other medications (particularly antipsychotIc medications). Trihexyphenidyl (Artane) works by blocking the actions of acetyl-choline, a NEUROTRANSMITTER that conveys nerve signals to muscle tissues. It can be given alone in tremor-predominant Parkinson’s disease or given adjunctively with other anti-Parkinson’s medications. Trihexyphenidyl also slows the response of smooth muscle tissue and can cause constipation and urinary retention. Other common side effects include drowsiness and dry mouth. Trihexyphenidyl should not be taken at the same time as tricyclic antidepressant medications, amanta-dine, or other anticholinergic medications.