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Methacholine

Systematic (IUPAC) name
2-(acetyloxy)-N,N,N-trimethylpropan-1-aminium
Identifiers
CAS number	55-92-5 62-51-1 (chloride)
ATC code	none
PubChem	1993
Chemical data
Formula	C8H18NO2+
Mol. mass	160.234 g/mol
SMILES	eMolecules & PubChem
Pharmacokinetic data
Bioavailability	?
Metabolism	?
Half life	?
Excretion	?
Therapeutic considerations
Pregnancy cat.	?
Legal status
Routes	?

Methacholine chloride (trade name Provocholine) is a synthetic choline ester that acts as a non-selective muscarinic receptor agonist in the parasympathetic nervous system.

Contents 1 Pharmacology 2 Uses 3 Contraindications 4 External links 5 References

[edit] Pharmacology

It is highly active at all of the muscarinic receptors, but has little effect on the nicotinic receptors. Methacholine has a charged quaternary amine structure, rendering it insoluble to lipid cell membranes. Clinically, this means that it will not cross the blood-brain barrier and has poor absorption from the gastrointestinal tract. It is broken down at a relatively slow rate within the body, due to its resistance to acetylcholinesterases.

[edit] Uses

The primary clinical use of methacholine is to diagnose bronchial hyperreactivity,^[1] which is the hallmark of asthma and also occurs in chronic obstructive pulmonary disease. This is accomplished through the bronchial challenge test. Other therapeutic uses are limited by its adverse cardiovascular effects, such as bradycardia and hypotension, which arise from its function as a cholinomimetic.

[edit] Contraindications

Use of methacholine, is contraindicated in patients with recent heart attack or stroke, uncontrolled hypertension, known severe airway disease, or an aortic aneurysm. It may be used with caution by nursing or pregnant mothers and patients taking certain medications for myasthenia gravis^[2].

[edit] External links

• Provocholine.com

[edit] References

• Katzung, Bertram G. (2004). Basic and Clinical Pharmacology (9th ed.). ISBN 0-07-141092-9. 
• Lötvall J, Inman M, O'Byrne P (May 1998). "Measurement of airway hyperresponsiveness: new considerations". Thorax 53: 419–424. PMID 9708238. http://thorax.bmjjournals.com/cgi/content/full/53/5/419. 

v • d • e Parasympathomimetics / cholinergic agonists / acetylcholinesterase inhibitors (N06DA, N07AA) Direct (at receptor) muscarinic: Muscarine  · Oxotremorine  · M1 (Vedaclidine • Xanomeline)  · M3 (Bethanechol, Pilocarpine, Arecoline, Cevimeline, Aceclidine, Alvameline)  · Methacholine nicotinic: Nicotine (low doses) · Lobeline · Varenicline · Epibatidine  · Dimethylphenylpiperazinium M & N: Acetylcholine/Choline alfoscerate · Carbachol Indirect/AIs (in synapse) Reversible very short acting: Edrophonium carbamates/stigmine: Ambenonium · Rivastigmine · Distigmine · tertiary/CNS (Physostigmine) · quaternary/peripheral (Neostigmine, Pyridostigmine) anti-dementia (Galantamine, Donepezil, Tacrine) Irreversible/ organophosphate ophthalmological (Ecothiopate, Isoflurophate, Demecarium) antiparasitic (Malathion, Metrifonate) chemical warfare (see Nerve agent)