How can i be less susceptible to the methacholine?

Limited Options!: This drug, a muscarinic receptor agonist, non-selectively causes smooth muscle contraction in the airways and is used to diagnose "reactive" airway diseases. It also may slow the heart rate, lower the blood pressure and cause excess secretion of the salivary glands. There is genetic specificity for these "receptors, " so that you may be able to "blame your genes" for your susceptibility! avoid it!