Version July 2025
| Medication | Minimum time to omit medication before challenge tests |
| Inhaled bronchodilators | |
| Albuterol | 6 hours |
| Levalbuterol | 6 hours |
| Terbutaline | 6 hours |
| Formoterol, salmeterol | 36 hours |
| Ultra long-acting beta agonists (eg, indacaterol, olodaterol, vilanterol) | 48 hours |
| Short-acting muscarinic antagonist (ipratropium) | 12 hours |
| Long-acting muscarinic antagonists (aclidinium, glycopyrrolate, tiotropium) | 1 week |
| Oral theophylline | 24 hours |
| Oral albuterol | 12 to 24 hours |
| Oral glucocorticoid* | 2 to 3 weeks |
| Cromolyn sodium¶ | 4 hours |
| Leukotriene modifiers (not typically withheld)Δ | 4 weeks |
| Inhaled glucocorticoids (not typically withheld)Δ | 4 weeks |
* The authors do not recommend routinely withholding oral glucocorticoids, but their anti-inflammatory effect may decrease bronchial responsiveness. A negative test while the patient is using glucocorticoids suggests that the patient's current symptoms are not due to asthma.
¶ Cromolyn has minimal effect on methacholine bronchoprovocation challenge, but should be withheld prior to allergen challenge.
Δ A single dose of inhaled glucocorticoids or leukotriene modifiers has minimal effect on methacholine challenge, but a withhold time of 4 to 8 weeks would be needed for full resolution of the anti-inflammatory effects. Negative testing on controller therapy suggests that the patient's current symptoms are not due to asthma.