The influence of ethanol infusion on the effects of 35% CO2 challenge. A study in panic disorder patients and healthy volunteers

Alcohol and Panic Disorders co-occur at a rate that exceeds chance significantly. Early experimental work suggests that alcoholic subjects, compared to non alcoholics, are less sensitive to sodium lactate and that alcohol intake reduces the response to a 35% CO2 challenge in Panic Disorder patients. The present study documents the direct pharmacological effect of ethanol infusion on CO2 induced panic. Methods: According to a placebo-controlled, double-blind, randomized, cross-over design 10 drug free Panic Disorder patients and 16 healthy volunteers underwent a 35% CO2 challenge after intravenous infusion of a moderate dose of ethanol on one test day and of placebo on another test day. Results: Compared to the placebo condition, the effect of the CO2 challenge was significantly smaller after ethanol infusion (p = 0.041). Discussion: A moderate dose of ethanol decreased the response to a 35% CO2 without inducing pre challenge sedation. Conclusion: the results comfort earlier findings of a direct pharmacological effect of ethanol on panic.