How can i prepare to pass a methacholine challenge?

Methacholin: Challenge is used if the diagnosis of asthma is in question. There is nothing to do to prepare to pass the test.you need to follow your doctors instructions exactly and stop any medications as directed. This is a potentially dangerous test and should only be done in a pulmonary function lab or in a doctors office with those trained to treat acute bronchospasm. It is better in ruling out asthma.