Methacholine Challenge

Overview

This test is used to diagnose asthma.

What will happen during the test?

During the test, you/your child will inhale doses of nebulized methacholine, a drug that causes the airway to tighten if you have asthma. We will monitor your lungs as this happens. If lung function drops more than 20% during this test then a diagnosis of asthma is made. A bronchodilator is given at the end of the test to reverse the effects of the methacholine.

Preparation

Before this study, any asthma medications that you are taking should not be given. These include:

  • Short acting bronchodilators (Albuterol/Maxair)
    Do not use for 6 hours prior to the test
  • Medium acting bronchodilators (Atrovent)
    Do not use for 8 hours prior to the test
  • Inhaled Steroids (Pulmicort, QVAR, Flovent)
    Do not take for 12 hours prior to the test
  • Leukotriene modifiers (Singulair, accolade)
    Do not take for 24 hours prior to the test
  • Oral bronchodilators
    • Liquid theophylline
      Do not take for 24 hours prior to the test
    • Intermediate acting theophylline
      Do not take for 48 hours prior to the test
  • Long acting bronchodilators (Serevent/Advair/Symbicort)
    Do not use for 36 prior to the test
  • Hydroxazine, cetrizine (Zyrtec)/Loratidine (Claritin)
    Do not take for 4 days prior to the test
  • Foods:
    • Caffeine (coffee, tea, chocolate, soda)
      Do not eat or drink for 12 hours prior to the test
    • Cough medicine is ok as long as it does not contain an antihistamine

Where do I go?

Go to the Pulmonary Function lab on the 6th floor of Shands at UF. Take the Atrium elevators to the 6th floor. When you get off the elevators go right. You will see the PFT lab straight ahead.

Results

Results will be available at the end of the study. Your doctor will discuss them with you at this time.