Hemodynamic responses to physostigmine in patients with a drug overdose.

Hemodynamic responses to physostigmine were evaluated in eight patients with coma due to overdose with mainly anticholinergic drugs (AC) and in five patients with coma due to overdose with nonanticholinergic drugs (NAC). After correction of hypovolemia, but before administration of physostigmine, AC patients had significantly lower systemic vascular resistances, slightly higher cardiac outputs, and lower mean arterial pressures than NAC patients. Physostigmine produced negligible hemodynamic and, as expected, negligible neurological changes in NAC patients. In AC patients physostigmine produced, also as expected, improved consciousness and in addition significantly increased mean arterial pressure, cardiac output, and cardiac work without significantly affecting systemic vascular resistance.