If exposure to a nerve agent is anticipated, pretreatment with pyridostigmine bromide 30 mg orally every 8 hours should be considered. This compound is a reversible carbamate anticholinesterase. Because pyridostigmine combines reversibly with acetylcholinesterase, it actually protects the enzyme from the essentially irreversible inhibition by subsequently delivered nerve agent; after the reversible bond is broken, the released cholinesterase can then help hydrolyze excess acetylcholine in target organs.
