 You will be put in one of two groups by chance as in the flip of a coin. One group will be taking placebo an inactive substance, the other group 180 mg pyridostigmine in time release formulation. Both placebo and pyridostigmine will look identical and will be taken as one capsule per day for 3 days. Neither you nor the study doctor will know at the time of treatment whether the treatment being given is active or inactive. However, in case of an emergency, this information will be available. 