Pyridostigmine

Structural formula
	Counterion (mostly bromide) not shown
General
Non-proprietary name	Pyridostigmine
other names	(1-methylpyridin-1-ium-3-yl) N , N -dimethylcarbamate ( IUPAC )
Molecular formula	C 9 H 13 N 2 O 2
External identifiers / databases
PubChem	4991
DrugBank	DB00545
Wikidata	Q419472
Drug information
ATC code	N07 AA02
Drug class	Parasympathomimetic
Mechanism of action	Cholinesterase inhibition
properties
Molar mass	181,21 g · mol -1
safety instructions
	Please note the exemption from the labeling requirement for drugs, medical devices, cosmetics, food and animal feed
GHS labeling of hazardous substances bromide; danger
H and P phrases	H: 300-310-317-330
	P: 260-264-280-284-302 + 350-310
Toxicological data	2.7 mg kg −1 ( LD 50 , mouse , ip )
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Pyridostigmine is an indirect parasympathomimetic that acts as a cholinesterase inhibitor and is mainly used to treat myasthenia gravis . It is used pharmacologically as a bromide salt ( pyridostigmine bromide ).

Effects

Pyridostigmine inhibits the enzyme acetylcholinesterase . This increases the concentration of the messenger substance acetylcholine at the motor end plate , which is used to antagonize non-depolarizing muscle relaxants and to treat myasthenia gravis . Also at the synapses of the parasympathetic nervous system, the acetylcholine concentration, and therefore also at a pyridostigmine increases intestinal - atony or urinary retention is used.

During the Second Gulf War (1991), for example, pyridostigmine was used for prophylaxis against poisoning with chemical warfare agents based on cholinesterase inhibitors because of this effect .

The increase in the acetylcholine level also results in undesirable effects. It can accommodation disorders of the eye, diarrhea , abdominal cramps, vomiting , nausea, salivation and bradycardia occur. In patients with obstructive airways disease, it can lead to dangerous narrowing of the bronchi ( bronchoconstriction ). Overdosing leads to a cholinergic crisis which, in addition to the symptoms mentioned, primarily causes a weakening of the respiratory muscles.

Contraindications

Pyridostigmine is contraindicated for mechanical occlusions of the intestinal or urinary tract . It must also not be taken in bronchial asthma and glaucoma . Insufficient data are available on effects during pregnancy and lactation ; it should not be used.

Pharmacokinetics

The bioavailability in the case of oral administration is low and fluctuates strongly (about 20%) due to the low absorption. Like neostigmine and distigmine , pyridostigmine is a quaternary amine compound that does not cross the blood-brain barrier . The plasma half-life is one to two hours, the majority of which is eliminated via the kidneys . This happens partly via metabolic products ( metabolites ), partly as an unchanged active ingredient.

Trade names

Kalymin (D), Mestinon (D, A, CH)

Web links

Entry on pyridostigmine at Vetpharm, accessed December 3, 2011.

Individual evidence

↑ ^a ^b Datasheet Pyridostigmine bromide from Sigma-Aldrich , accessed on April 22, 2011 ( PDF ).
↑ Entry on pyridostigmine in the ChemIDplus database of the United States National Library of Medicine (NLM) .
↑ Saskia Eckert: Development of a dynamic model for studying the protective effects of reversible acetylcholinesterase inhibitors against irreversible inhibition by highly toxic organophosphates (PDF; 1.3 MB) , dissertation at the University of Munich, 2006, p. 1.
↑ Szinicz, L. and Baskin, SI: Chemical and biological warfare agents . In: Textbook of Toxicology . WV mbH. Stuttgart: 865-895, 1999.

[Sigma-1] Datasheet Pyridostigmine bromide from Sigma-Aldrich , accessed on April 22, 2011 ( PDF ).

[ChemIDplus-2] Entry on pyridostigmine in the ChemIDplus database of the United States National Library of Medicine (NLM) .

[Eckert-3] Saskia Eckert: Development of a dynamic model for studying the protective effects of reversible acetylcholinesterase inhibitors against irreversible inhibition by highly toxic organophosphates (PDF; 1.3 MB) , dissertation at the University of Munich, 2006, p. 1.

[Szinicz-Baskin-4] Szinicz, L. and Baskin, SI: Chemical and biological warfare agents . In: Textbook of Toxicology . WV mbH. Stuttgart: 865-895, 1999.