Medications which may decrease airway hyperresponsiveness and withholding time
| Medication | Minimum time interval from last dose to MCT h | Reference(s) |
| Short-acting β-agonists in conventional inhaled doses (e.g. albuterol 200 μg) | 6 | [21, 22] |
| Long-acting β-agonists (e.g. salmeterol) | 36 | [23, 24] |
| Ultra-long-acting β-agonists (e.g. indacaterol, vilanterol, olodaterol) | 48 | [25] |
| Ipratropium (Atrovent 40 μg) | 12 | [26–28] |
| Long-acting anti-muscarinic agents | ≥168 | [29, 30] |
| Oral theophylline | 12–24 | [3] |
MCT: methacholine challenge test.