General Description
Procyclidine hydrochloride,α-cyclohexyl-α-phenyl-1-pyrrolidinepropanolhydrochloride (Kemadrin), was introduced in 1956. Althoughit is an effective peripheral anticholinergic and, indeed, hasbeen used for peripheral effects similar to its methochloride(i.e., tricyclamol chloride), its clinical usefulness lies inits ability to relieve voluntary muscle spasticity by its centralaction. Therefore, it has been used with success in thetreatment of Parkinson syndrome. It is said to be as effectiveas trihexyphenidyl and is used to reduce muscle rigidityin postencephalitic, arteriosclerotic, and idiopathic types ofthe disease. Its effect on tremor is not predictable and probablyshould be supplemented by combination with othersimilar drugs.
The toxicity of the drug is low, but when the dosageof the drug is high, side effects are noticeable. At therapeuticdosage levels, dry mouth is the most common sideeffect. The same care should be exercised with this drugas with all other anticholinergics when it is administeredto patients with glaucoma, tachycardia, or prostatichypertrophy.
Biochem/physiol Actions
Procyclidine is a synthetic anti-cholinergic agent and atropine-like antispasmodic. It exhibits therapeutic effects against Parkinson′s disease and schizophrenia. Procyclidine acts as a muscarinic receptor antagonist. It also affects N-methyl-D-aspartate (NMDA) glutamine and nicotinic acetylcholine receptors to a lower extent.
Metabolism
When given orally about one fifth of the dose is known
to be metabolised in the liver, principally by cytochrome
P450 and then conjugated with glucuronic acid.
Metabolites have been found in the urine.
