Nineteen patients (aged 6-19 years) with cystic fibrosis were randomly assigned to receive, in double-blind fashion, inhaled, buffered reduced glutathione (GSH) or placebo (sodium chloride with a hint of quinine) for 8 weeks. The treatments were administered 4 times a day (3 to 4 hours apart), for a total daily GSH dose of approximately 66 mg/kg of body weight. Primary outcomes were forced expiratory volume in 1 second (FEV1), forced vital capacity, forced expiratory flow at 25-75% of vital capacity, and peak flow; secondary outcomes were body mass index, 6-minute walk distance, and self-reported cough frequency, mucus production, wellness, improvement, and stamina. The mean change for peak flow was -6.5 L/min with placebo and +33.7 L/min with GSH (p = 0.04). Self-reported mean improvement on a scale from 1 to 5 (1 being much worse and 5 being much better) was 2.8 for placebo and 4.7 for GSH (p = 0.004). Of the 13 primary and secondary outcomes examined, 11 favored the treatment group over the placebo group (p = 0.002), indicating a general tendency of improvement in the GSH group. No significant side effects of GSH were reported.

Comment: Glutathione is a major antioxidant in lung tissue. Patients with cystic fibrosis have markedly decreased concentrations of total (oxidized plus reduced) glutathione in the epithelial lining fluid of the lung. Anecdotal reports suggest that nebulized glutathione administered by aerosol can relieve symptoms and improve clinical outcome in patients with chronic obstructive pulmonary disease. The results of the present study indicate that glutathione is also beneficial for the chronic lung disease that occurs in patients with cystic fibrosis.

Bishop C, et al. A pilot study of the effect of inhaled buffered reduced glutathione on the clinical status of patients with cystic fibrosis. Chest 2005;127:308-317.