Methacholine Challenge

A diagnostic test that uses the drug Methacholine to determine if a patient’s breathing tubes (bronchi) are hyperreactive (twitchy).

The purpose is to diagnose asthma in patients when all other pulmonary function tests are normal or do not indicate that asthma is present.

How is a Methacholine Challenge Test Performed?
Methacholine is inhaled in increasing doses with five inhalations at each concentration. After the inhalation, a spirometry, or breathing test, is done.

Expiratory flow rates are monitored during the test. The peak effect occurs within one to four minutes. The duration of effect lasts 15-75 minutes. At the conclusion of the test, a bronchodilator is administered to reverse any effects of the methacholine.

What happens after a Methacholine Challenge Test?
When the test is finished, a respiratory therapist will observe you until you are stable. Report any symptoms of chest tightness, throat irritation, itching, headache, difficulty in breathing, or lightheadedness.

Your physician will review the test results at your next office visit. Contact your physician if you have any questions or problems after your Methacholine Challenge Test.

Quick Links: Pulmonary Function Testing Exercise Physiology or Cardiopulmonary Exercise Test (CPX) Broncho Pulmonary Challenge

Medications to be stopped before Methacholine Challenge test: Albuterol, Proventil, Ventolin – 8 hours Maxair – 8 Hours Atrovent, Combivent, Spiriva – 24 hours Serevent, Advair, Flovent, Pulmicort, Qvar, Foradil - 48 hours Brethine, Proventil Tabs - 24 hours Intal - 8 hours Tilade - 48 hours Accolate, Singulair, Zyflo- 24 hours Zyrtec, Atarax - 72 hours No coffee, tea, cola, chocolate, or smoking on the day of the test