Health Topics

Methacholine is a drug which may cause the airways to narrow. Your child will breathe in very low doses of methacholine by a mist aerosol and then have spirometry measured. Doses of inhaled methacholine will be gradually increased with spirometry recorded after each dose. The testing will be completed if your child either shows signs by spirometry that the airways are narrowing, or reaches the highest dose used in the test without airway narrowing.

The test takes up to two hours.  

There is a list of medications that may decrease your child's response to the methacholine and should be avoided only if possible prior to testing.

Check with your child's physician before stopping any medication prior to this test, or call the PFT Laboratory at 513-636-8049. Download patient instructions (.pdf).

Thousands of methacholine challenge tests have been performed in Cincinnati Children's pulmonary function laboratory and elsewhere with no serious side effects.

Methacholine causes airway narrowing; however, all precautions are taken including continuous monitoring and administration of an inhaled bronchodilator to your child if any airway narrowing is observed.