Physostigmine-induced myoclonus in Alzheimer's disease

Physostigmine caused myoclonus in two patients with Alzheimer's disease during a clinical trial. Neither patient had myoclonus before or after physostigmine treatment. We hypothesize that physostigmine reduced the sensitivity of the remaining muscarinic receptors in these two patients, altering the interaction between cholinergic and either serotoninergic or dopaminergic neurotransmitter systems.