Physostigmine reversal of drug-induced paradoxical excitement.

Paradoxical excitement associated with intravenous conscious-sedation in a patient undergoing dental surgery was successfully reversed with 1.0 mg physostigmine. Physostigmine is felt to have exerted this effect by 2 mechanisms: the re-establishment of homeostasis in the CNS via augmented cholinergic pathways with the net result being thalamacocortical excitation, and cholinergically-mediated increase in cerebral blood flow increasing the rate of redistribution of the intravenous sedative agents used. The most commonly encountered side-effects of physostigmine used to reverse parodoxical excitement, emergence delirium, or prolonged narcosis are bradycardia, nausea, and/or vomiting. The incidence of these side-effects is low in doses, below 2.0 mg/70 kg. body weight.