Pyridostigmine is used to treat muscle weakness in people with myasthenia gravis or forms of congenital myasthenic syndrome and to combat the effects of curariform drug toxicity. Pyridostigmine bromide has been FDA approved for military use during combat situations as an agent to be given prior to exposure to the nerve agent Soman in order to increase survival. Used in particular during the first Gulf War, pyridostigmine bromide has been implicated as a causal factor in Gulf War syndrome.[7][8]
With pyridostigmine classified as a type of parasympathomimetic, it can be used to treat underactive bladder.[9]
Pyridostigmine bromide is contraindicated in cases of mechanical intestinal or urinary obstruction and should be used with caution in patients with bronchial asthma.[13][14]
Pyridostigmine inhibits acetylcholinesterase in the synaptic cleft, thus slowing down the hydrolysisofacetylcholine. Like its predecessor neostigmine, it is a quaternary carbamate inhibitor of cholinesterase that does not cross the blood–brain barrier. It carbamylates about 30% of peripheral cholinesterase enzyme, and the carbamylated enzyme eventually regenerates by natural hydrolysis and excess acetylcholine (ACh) levels revert to normal.
The ACh diffuses across the synaptic cleft and binds to receptors on the post synaptic membrane, causing an influx of sodium (Na+,) resulting in depolarization. If large enough, this depolarization results in an action potential. To prevent constant stimulation once the ACh is released, an enzyme called acetylcholinesterase is present in the endplate membrane close to the receptors on the post synaptic membrane, and quickly hydrolyses ACh.
^ abcdefghi"Neostigmine Bromide". The American Society of Health-System Pharmacists. Archived from the original on 21 December 2016. Retrieved 8 December 2016.
^World Health Organization (2019). World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
^Gales BJ, Gales MA (February 2007). "Pyridostigmine in the treatment of orthostatic intolerance". The Annals of Pharmacotherapy. 41 (2): 314–318. doi:10.1345/aph.1H458. PMID17284509. S2CID22855759.
^ abGales BJ, Gales MA (February 2007). "Pyridostigmine in the treatment of orthostatic intolerance". The Annals of Pharmacotherapy. 41 (2): 314–318. doi:10.1345/aph.1H458. PMID17284509. S2CID22855759.
^Kanjwal K, Karabin B, Sheikh M, Elmer L, Kanjwal Y, Saeed B, Grubb BP (June 2011). "Pyridostigmine in the treatment of postural orthostatic tachycardia: a single-center experience". Pacing and Clinical Electrophysiology. 34 (6): 750–755. doi:10.1111/j.1540-8159.2011.03047.x. PMID21410722. S2CID20405336.
