Kemadrin is a brand name for the medication procyclidine, which belongs to a class of drugs known as anticholinergics or antispasmodics. It is primarily used to treat symptoms of Parkinson's disease or involuntary movements due to the side effects of certain psychiatric drugs (such as antipsychotics). Kemadrin works by blocking the action of acetylcholine, a chemical messenger in the brain that helps control muscle movement. By doing so, it helps reduce muscle stiffness, tremors, and other symptoms of Parkinson's disease, as well as controlling extrapyramidal symptoms caused by other medications. It is usually taken orally, in tablet form, and the dosage depends on the patient's condition and response to treatment.