parasympatomimeetit

Parasympathomimetics, also known as cholinergic agonists, are a class of drugs that mimic or enhance the effects of the neurotransmitter acetylcholine in the parasympathetic nervous system. This system is responsible for the "rest and digest" functions of the body, promoting actions such as slowing heart rate, increasing intestinal and glandular activity, and relaxing sphincter muscles.

These drugs work by either directly stimulating muscarinic or nicotinic receptors, or by inhibiting the enzyme acetylcholinesterase, which breaks down acetylcholine. Direct-acting agents bind to and activate these receptors, while indirect-acting agents increase the availability of acetylcholine at the synapse.

Parasympathomimetics have various therapeutic applications. They are used to treat conditions like glaucoma by reducing intraocular pressure, myasthenia gravis by improving muscle strength, and urinary retention by stimulating bladder contraction. They can also be used as diagnostic agents or in reversal of neuromuscular blockade.

However, due to their broad effects on the parasympathetic system, parasympathomimetics can also cause side effects. These often include gastrointestinal distress such as nausea, vomiting, and diarrhea, as well as increased salivation, sweating, bradycardia, and bronchoconstriction. Careful dosing and patient monitoring are essential when using these medications.