Parasympathomimetic drug

Parasympathomimetic (plural of parasympathomimetic ) are drugs which mimic the effects of the parasympathetic nervous system. It acetylcholine is used as a messenger. A distinction is made between direct and indirect parasympathomimetic.

• Direct parasympathomimetic agents such as carbachol, bethanechol, methacholine, pilocarpine or arecoline grab as agonists directly to the muscarinic acetylcholine receptors. The endogenous acetylcholine would be unsuitable for pharmacological therapy, as it is inactivated within milliseconds by the cholinesterases.

• Indirect parasympathomimetic agents such as physostigmine, rivastigmine, neostigmine, pyridostigmine or inhibit cholinesterases and thus the breakdown of acetylcholine. The term " indirect parasympathomimetic " is here, however, ill-chosen, since acetylcholine occurs as a transmitter in both the parasympathetic nervous system, in sympathetic and at the motor end plate of the skeletal muscle and the acetylcholinesterase is inhibited there.

Parasympathomimetic effects of these materials include a narrowing of the pupils, a stimulation of the salivary flow as well as therapeutic effects in bowel and bladder atonia.

Those cholinesterase inhibitors that also develop central nervous system effects, can be used in mild to moderate Alzheimer's disease ( rivastigmine, donepezil, galantamine, tacrine only rarely ). Their effectiveness is controversial.