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Record Information
StatusExpected but not Quantified
Creation Date2012-09-06 15:16:50 UTC
Update Date2020-02-26 21:40:08 UTC
Secondary Accession Numbers
  • HMDB14685
Metabolite Identification
Common NamePyridostigmine
DescriptionPyridostigmine is only found in individuals that have used or taken this drug. It is a cholinesterase inhibitor with a slightly longer duration of action than neostigmine. It is used in the treatment of myasthenia gravis and to reverse the actions of muscle relaxants. [PubChem]Pyridostigmine inhibits acetylcholinesterase in the synaptic cleft by competing with acetylcholine for attachment to acetylcholinesterase, thus slowing down the hydrolysis of acetylcholine, and thereby increases efficiency of cholinergic transmission in the neuromuscular junction and prolonges the effects of acetylcholine.
Pyridine N-oxideHMDB
Pyridostigmine bromideHMDB
Pyridostigmine bromineHMDB
Bromide, pyridostigmineHMDB
Chemical FormulaC9H13N2O2
Average Molecular Weight181.2117
Monoisotopic Molecular Weight181.09770267
IUPAC Name3-[(dimethylcarbamoyl)oxy]-1-methylpyridin-1-ium
Traditional Namepyridostigmine
CAS Registry Number155-97-5
InChI Identifier
Chemical Taxonomy
Description belongs to the class of organic compounds known as n-methylpyridinium compounds. These are methylpyridines that carry a methyl group at the 1-position.
KingdomOrganic compounds
Super ClassOrganoheterocyclic compounds
ClassPyridines and derivatives
Sub ClassMethylpyridines
Direct ParentN-methylpyridinium compounds
Alternative Parents
  • N-methylpyridinium
  • Pyridinium
  • Carbamic acid ester
  • Heteroaromatic compound
  • Carbonic acid derivative
  • Azacycle
  • Organic oxide
  • Organopnictogen compound
  • Organic oxygen compound
  • Organooxygen compound
  • Organonitrogen compound
  • Organic nitrogen compound
  • Carbonyl group
  • Hydrocarbon derivative
  • Organic cation
  • Aromatic heteromonocyclic compound
Molecular FrameworkAromatic heteromonocyclic compounds
External Descriptors
Physiological effect

Health effect:


Route of exposure:


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Physical Properties
Experimental Properties
Melting Point153 °CNot Available
Boiling PointNot AvailableNot Available
Water Solubility1.04 g/LNot Available
LogP1.554Not Available
Predicted Properties
Water Solubility1.04 g/LALOGPS
pKa (Strongest Acidic)19.53ChemAxon
Physiological Charge1ChemAxon
Hydrogen Acceptor Count1ChemAxon
Hydrogen Donor Count0ChemAxon
Polar Surface Area33.42 ŲChemAxon
Rotatable Bond Count2ChemAxon
Refractivity49.66 m³·mol⁻¹ChemAxon
Polarizability19.38 ųChemAxon
Number of Rings1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterNoChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleNoChemAxon
Spectrum TypeDescriptionSplash KeyView
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, Positivesplash10-0006-9700000000-144f11d8d4fca931e26fSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-001i-4900000000-505a3902a67894832786Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-001j-7900000000-f2fb1dbcea23a916a60dSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0005-9100000000-5851c472c0f98c9da49eSpectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-001i-1900000000-4020266c0445cc9e4d81Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-00lr-9700000000-76c2110cb7085d434fd7Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-007c-9000000000-bf72b6b775960258441eSpectrum
Biological Properties
Cellular Locations
  • Cytoplasm
  • Membrane
Biospecimen Locations
  • Blood
  • Urine
Tissue Locations
  • Kidney
  • Liver
Normal Concentrations
BloodExpected but not QuantifiedNot QuantifiedNot AvailableNot AvailableTaking drug identified by DrugBank entry DB00545 details
UrineExpected but not QuantifiedNot QuantifiedNot AvailableNot AvailableTaking drug identified by DrugBank entry DB00545 details
Abnormal Concentrations
Not Available
Predicted Concentrations
BiospecimenValueOriginal ageOriginal sexOriginal conditionComments
Blood0.000 uMAdult (>18 years old)BothNormalPredicted based on drug qualities
Blood0.000 umol/mmol creatinineAdult (>18 years old)BothNormalPredicted based on drug qualities
Associated Disorders and Diseases
Disease ReferencesNone
Associated OMIM IDsNone
DrugBank IDDB00545
Phenol Explorer Compound IDNot Available
FooDB IDNot Available
KNApSAcK IDNot Available
Chemspider ID4817
KEGG Compound IDC07410
BioCyc IDNot Available
BiGG IDNot Available
Wikipedia LinkPyridostigmine
METLIN IDNot Available
PubChem Compound4991
PDB IDNot Available
ChEBI ID257330
Food Biomarker OntologyNot Available
VMH IDNot Available
MarkerDB ID
Synthesis ReferenceNot Available
Material Safety Data Sheet (MSDS)Not Available
General References
  1. Singer W, Opfer-Gehrking TL, McPhee BR, Hilz MJ, Bharucha AE, Low PA: Acetylcholinesterase inhibition: a novel approach in the treatment of neurogenic orthostatic hypotension. J Neurol Neurosurg Psychiatry. 2003 Sep;74(9):1294-8. [PubMed:12933939 ]


General function:
Involved in carboxylesterase activity
Specific function:
Terminates signal transduction at the neuromuscular junction by rapid hydrolysis of the acetylcholine released into the synaptic cleft. Role in neuronal apoptosis.
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  1. Drake-Baumann R, Seil FJ: Effects of exposure to low-dose pyridostigmine on neuromuscular junctions in vitro. Muscle Nerve. 1999 Jun;22(6):696-703. [PubMed:10366222 ]
  2. Ricordel I, Meunier J: [Chemical weapons: antidotes. View about the real means, perspectives]. Ann Pharm Fr. 2000 Jan;58(1):5-12. [PubMed:10669805 ]
  3. Prasad V, Scotch R, Chaudhuri AR, Walss C, Fathy DB, Miller C, Luduena RF: Interactions of bovine brain tubulin with pyridostigmine bromide and N,N'-diethyl-m-toluamide. Neurochem Res. 2000 Jan;25(1):19-25. [PubMed:10685600 ]
  4. Sinton CM, Fitch TE, Petty F, Haley RW: Stressful manipulations that elevate corticosterone reduce blood-brain barrier permeability to pyridostigmine in the Rat. Toxicol Appl Pharmacol. 2000 May 15;165(1):99-105. [PubMed:10814558 ]
  5. Servatius RJ, Ottenweller JE, Guo W, Beldowicz D, Zhu G, Natelson BH: Effects of inescapable stress and treatment with pyridostigmine bromide on plasma butyrylcholinesterase and the acoustic startle response in rats. Physiol Behav. 2000 May;69(3):239-46. [PubMed:10869589 ]
  6. Chen X, Ji ZL, Chen YZ: TTD: Therapeutic Target Database. Nucleic Acids Res. 2002 Jan 1;30(1):412-5. [PubMed:11752352 ]
General function:
Involved in carboxylesterase activity
Specific function:
Esterase with broad substrate specificity. Contributes to the inactivation of the neurotransmitter acetylcholine. Can degrade neurotoxic organophosphate esters.
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  1. Somani SM, Husain K, Asha T, Helfert R: Interactive and delayed effects of pyridostigmine and physical stress on biochemical and histological changes in peripheral tissues of mice. J Appl Toxicol. 2000 Jul-Aug;20(4):327-34. [PubMed:10942908 ]
  2. Servatius RJ, Ottenweller JE, Guo W, Beldowicz D, Zhu G, Natelson BH: Effects of inescapable stress and treatment with pyridostigmine bromide on plasma butyrylcholinesterase and the acoustic startle response in rats. Physiol Behav. 2000 May;69(3):239-46. [PubMed:10869589 ]
  3. Abou-Donia MB, Wilmarth KR, Abdel-Rahman AA, Jensen KF, Oehme FW, Kurt TL: Increased neurotoxicity following concurrent exposure to pyridostigmine bromide, DEET, and chlorpyrifos. Fundam Appl Toxicol. 1996 Dec;34(2):201-22. [PubMed:8954750 ]
General function:
Involved in monooxygenase activity
Specific function:
Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It performs a variety of oxidation reactions (e.g. caffeine 8-oxidation, omeprazole sulphoxidation, midazolam 1'-hydroxylation and midazolam 4-hydroxylation) of structurally unrelated compounds, including steroids, fatty acids, and xenobiotics. Acts as a 1,8-cineole 2-exo-monooxygenase. The enzyme also hydroxylates etoposide.
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  1. Preissner S, Kroll K, Dunkel M, Senger C, Goldsobel G, Kuzman D, Guenther S, Winnenburg R, Schroeder M, Preissner R: SuperCYP: a comprehensive database on Cytochrome P450 enzymes including a tool for analysis of CYP-drug interactions. Nucleic Acids Res. 2010 Jan;38(Database issue):D237-43. doi: 10.1093/nar/gkp970. Epub 2009 Nov 24. [PubMed:19934256 ]