indication

For the treatment of all forms of Parkinson's Disease, as well as control of extrapyramidal reactions induced by antipsychotic agents.

pharmacology

Procyclidine has an atropine-like action on parasympathetic-innervated peripheral structures including smooth muscle. It's antispasmodic effects are thought to be related to the blockage of central cholinergic receptors M1, M2 and M4. It is used to treat symptomatic Parkinsonism and extrapyramidal dysfunction caused by antipsychotic agents.

mechanism of action

The mechanism of action is unknown. It is thought that Procyclidine acts by blocking central cholinergic receptors, and thus balancing cholinergic and dopaminergic activity in the basal ganglia. Many of its effects are due to its pharmacologic similarities with atropine. Procyclidine exerts an antispasmodic effect on smooth muscle, and may produce mydriasis and reduction in salivation.

toxicity

LD₅₀=60 mg/kg (IV in mice)

drug interactions

Donepezil: Possible antagonism of action

Galantamine: Possible antagonism of action

Haloperidol: The anticholinergic increases the risk of psychosis and tardive dyskinesia

Tacrine: The therapeutic effects of the central acetylcholinesterase inhibitor, Tacrine, and/or the anticholinergic, Procyclidine, may be reduced due to antagonism. The interaction may be beneficial when the anticholinergic action is a side effect. Monitor for decreased efficacy of both agents.

Trimethobenzamide: Trimethobenzamide and Procyclidine, two anticholinergics, may cause additive anticholinergic effects and enhance their adverse/toxic effects. Monitor for enhanced anticholinergic effects.

Triprolidine: Triprolidine and Procyclidine, two anticholinergics, may cause additive anticholinergic effects and enhance their adverse/toxic effects. Monitor for enhanced anticholinergic effects.

Trospium: Trospium and Procyclidine, two anticholinergics, may cause additive anticholinergic effects and enhanced adverse/toxic effects. Monitor for enhanced anticholinergic effects.