EFFECT OF PYRIDOSTIGMINE BROMIDE ON ACCELERATION TOLERANCE AND PERFORMANCE

Pyridostigmine Bromide (PB) is used as a pre-exposure antidote for the prevention of potentially lethal effects of certain chemical warfare nerve agents by reversibly inhibiting acetylcholinesterase (AChE). Thi s study was designed to determine whether PB has any deleterious effec ts on acceleration tolerance (+Gz) or performance. Double-blind placeb o trials were conducted to evaluate the effects of PB (90 mg) per day on +Gx tolerances and performance. Three types of exposures were used: 1) gradual onset rate (GOR) exposures of 0.1 G/s; 2) a series of rapi d onset rate (ROR) exposures of 6.0 G/s; and 3) a simulated aerial com bat maneuver (SACM) of 4.5 to 9.0 +Gz. Performance tasks included the Unified Tri-Service Cognitive Performance Assessment Battery (UTC-PAB) . The subjects were not able to correlate their symptoms with PB, plac ebo, or the acceleration exposure itself. Plasma PB individual levels ranged between 6 and 31 ng/ml and AChE levels of inhibition had a rang e of 12 to 45%. There were no significant effects on +Gz tolerance or performance related to PB. Based on the results of this study, PB does not significantly alter +Gz tolerance or performance. Therefore, we d o not expect aircrew taking prophylactic doses of PB to be adversely a ffected during aerial combat operations.