Toxic psychosis due to antiparkinsonian drugs

Nine cases of transient toxic-delirious reactions during combined antipsychotic-antiparkinsonism treatment have been described. A few days prior to the onset of the reaction, all patients had been placed on an antiparkinsonian drug.

Three clinical phases were observed: an autonomic stage (sympathicotonic signs: mydriasis, dry mouth, anorexia, excitement, disorientation, insomnia, severe constipation); a strio-thalamic phase (dyskinesias, visual and tactile hallucinations) and a post-delirious state (increased sleep and integration).

The pathogenic factors which play a role in this atropine-like toxic condition, such as age, individual susceptibility, drug response per se and the influence of rapid dose changes were briefly discussed.