methacholine

Methacholine is a synthetic choline ester and parasympathomimetic bronchoconstrictor used primarily as a diagnostic agent in the methacholine challenge test to assess bronchial airway hyperreactivity, most commonly for diagnosing asthma. It acts as a non-selective muscarinic receptor agonist, stimulating muscarinic receptors (especially M3) on airway smooth muscle to induce bronchoconstriction. Methacholine does not cross the blood–brain barrier due to its quaternary ammonium structure and is relatively resistant to breakdown by acetylcholinesterases. The drug was approved by the FDA in 1986 and is marketed under the brand name Provocholine[1][2][5][8].

Brand names

Provocholine

Other names

methacholine chlorideacetyl-β-methylcholine