Effect of oral corticosteroids on mucus clearance by cough and mucociliary transport in stable asthma.

Inhaled radioaerosol particles have been used to assess mucus clearance in 12 patients with stable asthma. Patients who coughed frequently showed faster clearance than those who coughed infrequently. Treatment with medium and high dose oral corticosteroids reduced coughing and thereby reliance on mucus transport by cough. Despite this, and despite increased penetration of the particles into the bronchial tree, mean particle clearance was slightly faster after four week treatment (two weeks on 15 mg prednisolone orally each day, plus two weeks on 30 mg). Mean clearance remained, however, markedly slower than in normal subjects. Five patients who were initially sputum producers (mean 1.4 g . h-1) ceased to produce sputum after four week treatment.