FDA approved Provocholine (methacholine chloride) for Bronchial Airway Hyperreactivity DiagnosisFDA approved new test to help diagnose asthma in certain patients

Provocholine (methacholine chloride) is a cholinergic agonist that causes bronchoconstriction by stimulating muscarinic receptors in airway smooth muscle. In patients with bronchial airway hyperreactivity, inhalation of methacholine leads to a greater than normal reduction in forced expiratory volume in 1 second (FEV1).

Provocholine, used in a methacholine challenge test, is indicated for the diagnosis of bronchial airway hyperreactivity in adults and pediatric patients five years of age and older who do not have clinically apparent asthma.

The methacholine challenge test should be conducted in a pulmonary function laboratory or clinic by adequately trained personnel. Baseline FEV1 must be ≥60% predicted (adults and children) and ≥1.5 L (adults). Provocholine is administered via nebulization using either the 5-Breath Dosimeter Dosing Method or the 2-Minute Tidal Breathing Dosing Method with doubling or quadrupling stepwise protocols. The test is positive if FEV1 decreases by ≥20% from post-diluent FEV1. An inhaled β-agonist should be given after the test.

Trial data not available in label.

Contraindicated in patients with clinically apparent asthma, wheezing, or baseline FEV1 <60% predicted (adults and children) or <1.5 L (adults). Emergency medication and equipment must be available. Use caution in patients on chronic asthma drugs; only administer if accuracy of asthma diagnosis is in doubt and spirometry is normal after supervised withdrawal of asthma drugs.

Provocholine is a diagnostic agent for confirming bronchial airway hyperreactivity in patients with suspected asthma but without clinically apparent asthma. It should be used only when baseline spirometry is normal and asthma is not clinically evident. The test helps differentiate asthma from other causes of respiratory symptoms.