Pyridostigmine is probably the anticholinesterase of choice in the majority of patients with myasthenia gravis. The half-life of the drug is reasonably long (90 min) but it does not accumulate easily. It can be given orally as a tablet or elixir and has relatively mild cholinergic side-effects. It is frequently used to improve muscle strength, but only produces symptomatic improvement and does not correct the basic pathophysiological problem. If given in too large a dosage, anticholinesterase drugs produce cholinergic neuromuscular blockade and increase muscle weakness. In the longer term, these drugs can damage the neuromuscular junction itself. Anticholinesterase drugs can produce cholinergic side-effects such as excessive salivation, abdominal cramps and diarrhea, sweating, and bradycardia. An average dose of pyridostigmine would be 30 to 60 mg four or five times daily.
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