indication

Used for the symptomatic treatment of parkinsonism.

pharmacology

Metixene is a tertiary antimuscarinic with actions similar to those of atropine; it also has antihistaminic and direct antispasmodic properties. It is used for the symptomatic treatment of parkinsonism, including the alleviation of the extrapyramidal syndrome induced by other drugs such as phenothiazines, but, like other antimuscarinics, it is of no value against tardive dyskinesias. Metixene has been discontinued.

mechanism of action

Parkinsonism is thought to result from an imbalance between the excitatory (cholinergic) and inhibitory (dopaminergic) systems in the corpus striatum. The mechanism of action of centrally active anticholinergic drugs such as metixene is considered to relate to competitive antagonism of acetylcholine at muscarinic receptors in the corpus striatum, which then restores the balance.

toxicity

Signs of overdose include dilated and sluggish pupils, warm, dry skin, facial flushing, decreased secretions of the mouth, pharynx, nose, and bronchi, foul-smelling breath, elevated temperature, tachycardia, cardiac arrhythmias, decreased bowel sounds, urinary retention, delirium, disorientation, anxiety, hallucinations, illusions, confusion, incoherence, agitation, hyperactivity, ataxia, loss of memory, paranoia, combativeness, and seizures.

biotransformation

Hepatic. Metabolism occurs via sulfoxydation and N-demethylation.

absorption

Absorbed in the gastrointestinal tract following oral administration, however the extent of absorption is not known.