Methacholine challenge test

Your Doctor has ordered this test to help him determine if you have asthma and if so how severe. Methacholine is similar to a normal body substance that causes narrowing of the airways, if you have asthma. Prior to this test you will have performed a full Pulmonary Function test. This test’s results will be reviewed and the Cardio Respiratory secretary will contact you with the appointment time for the Methacholine Challenge test.

Steps of this test

Step 1: Perform 3 baseline spirometry (quick breathing tests) measures lung function.

Step 2: Breathe in mists starting with salt water; then increasing dosages of Methacholine; 3 spirometry tests done between each mist.

Step 3: If testing drops by 20% no more methacholine will be given and Ventolin (bronchodilator) is administered to reverse any changes.

Step 4: Spirometry is done prior to leaving to confirm lung function is back to normal.

What you should know

This test could take up to 60 minutes to complete.

Do not drink coffee or smoke for 4 hours prior to test

The following drugs should be stopped:

For 6 hours

• ventolin (salbutamol)
• berotec (fenoterol)
• bricanyl (terbutaline)
• oxeze (formoterol)

For 12 hours

• accolate (zafirlukast)
• servent (salmeterol)
• atrovent (ipratropium)
• singular (montelukast)
• advair (contains servent)
• symbicort (contains oxeze)
• spirivia (tiotropium)

For 48 hours

• Theophylline (uniphyl, theor-dur)

Any questions contact cardio-respiratory department 613-938-5388