Parasympathetic drugs that inhibit or inactivate the enzyme acetylcholinesterase, allowing prolonged activity of acetylcholine. They cause miosis and ciliary muscle contraction. There are two groups: reversible which are of short duration (up to 12 hours or so), such as neostigmine, physostigmine and edrophonium chloride, and irreversible which lasts for days or weeks, such as demecarium bromide and diisopropyl fluorophosphate (DFP).
See acetylcholinesterase;
miotics.