Drug Interaction Report

ADJUST DOSING INTERVAL: Anticholinergics, beta-agonists, and theophylline may inhibit the bronchial airway response to methacholine. Methacholine is a cholinergic agonist that binds muscarinic receptors in bronchial smooth muscle, which leads to bronchoconstriction. Since patients with asthma exhibit greater sensitivity to induced bronchoconstriction than healthy subjects, methacholine is used to diagnose bronchial airway hyperreactivity in the absence of clinically apparent asthma. Bronchodilation caused by anticholinergics, beta-agonists, and theophylline may counteract methacholine-induced bronchoconstriction, possibly leading to diagnostic failure.

MANAGEMENT: Treatment with anticholinergics, beta-agonists, and theophylline should be interrupted before methacholine administration for the following durations:
--Short-acting anticholinergics (e.g., ipratropium): 12 hours
--Long-acting anticholinergics (e.g., tiotropium): At least 168 hours
--Short-acting beta-agonists (e.g., albuterol): 6 hours
--Long-acting beta-agonists (e.g., salmeterol): 36 hours (some authorities recommend 48 hours for ultra-long-acting beta-agonists [e.g., indacaterol, olodaterol, vilanterol])
--Oral theophylline: 12 to 48 hours

ADJUST DOSING INTERVAL: Anticholinergics, beta-agonists, and theophylline may inhibit the bronchial airway response to methacholine. Methacholine is a cholinergic agonist that binds muscarinic receptors in bronchial smooth muscle, which leads to bronchoconstriction. Since patients with asthma exhibit greater sensitivity to induced bronchoconstriction than healthy subjects, methacholine is used to diagnose bronchial airway hyperreactivity in the absence of clinically apparent asthma. Bronchodilation caused by anticholinergics, beta-agonists, and theophylline may counteract methacholine-induced bronchoconstriction, possibly leading to diagnostic failure.

MANAGEMENT: Treatment with anticholinergics, beta-agonists, and theophylline should be interrupted before methacholine administration for the following durations:
--Short-acting anticholinergics (e.g., ipratropium): 12 hours
--Long-acting anticholinergics (e.g., tiotropium): At least 168 hours
--Short-acting beta-agonists (e.g., albuterol): 6 hours
--Long-acting beta-agonists (e.g., salmeterol): 36 hours (some authorities recommend 48 hours for ultra-long-acting beta-agonists [e.g., indacaterol, olodaterol, vilanterol])
--Oral theophylline: 12 to 48 hours