Distigmine is an acetylcholinesterase (AChE) inhibitor. Distigmine shows direct binding to muscarinic receptors in the rat bladder, and repeated oral administration of distigmine causes downregulation of muscarinic receptors in the rat bladder. The observed direct interaction of distigmine with the bladder muscarinic receptors may partly contribute to the therapeutic and/or side effects seen in the treatment of detrusor underactivity. It is usually used to treat myasthenia gravis, dysuria due to hypotonic bladder such as neurogenic bladder or after surgery. Common side effects are: nausea/vomiting, abdominal pain, diarrhea, increased salivation, hypersecretion in respiratory tract, sweating, bradycardia, miosis, difficulty in breathing. Distigmine has a greater risk of causing cholinergic crisis because of accumulation of the drug being more likely than with neostigmine or pyridostigmine and so distigmine is rarely used as a treatment for myasthenia gravis, unlike pyridostigmine and neostigmine.