Antimuscarinic

The antimuscarinic agents are much less efficacious than levodopa and play only an adjuvant role in antiparkinsonism therapy. The actions of benztropine, trihexyphenidyl, procyclidine, and biperiden are similar, although individual patients may respond more favorably to one drug. Each of these drugs can induce mood changes and produce xerostomia (dryness of the mouth) and visual problems, as do all muscarinic blockers. They interfere with gastrointestinal peristalsis and are contraindicated in patients with glaucoma, prostatic hyperplasia, or pyloric stenosis. Blockage of cholinergic transmission produces effects similar to augmentation of dopaminergic transmission (again, because of the creation of an imbalance in the dopamine/acetylcholine ratio