Methacholine Challenge Testing
A Methacholine challenge is a test to determine if you have asthma. It is performed by inhaling a medication (methacholine) in increasing doses in an attempt to produce a change in your pulmonary function test results.
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The test will continue until you reach at least a 20% drop in your FEVI (the amount of air you exhale in the first second) or you finish all the dosages of the medication. |
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After the testing is completed, you may be given a nebulizer treatment that will reverse the action of the methacholine, if it has caused your results to change. |
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After each dose and after the breathing (nebulizer) treatment, you will be asked to perform several breathing tests. |
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The testing time varies and may take up to 2 hours, depending on how you do. |
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You may have some mild shortness of breath from taking the medication. True asthma attacks are very rare and generally respond promptly to treatment. |
Prior to coming in for testing, you will be asked not to take some of your morning medications:
The following medications need to be avoided 48 hours prior to testing.
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Oral bronchodilators--Slobid, Theodur, Uniphyll, Unidur, Theophylline |
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Antihistamines--Claritin (regular and D), Allegra (regular and D), Benadryl, Bromfed, Atrohist, and over-the counter cold, cough and sinus medications. |
The following medications need to be avoided 24 hours prior to testing.
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Oral steroids--Prednisone, Medrol, Methylpredisolone |
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Oral bronchodilators--Proventil Repetabs |
The following medications need to be avoided 12 hours prior to testing:
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Bronchodilators--Albuterol, Ventoline, Proventil, Maxair, Brethaire, Serevent, Atrovent, Combivent |
Avoid all caffeine 6 hours prior to testing. NORMAL DIET - no fasting is necessary