Efficacy and safety of oral sildenafil in cystic fibrosis children with mild to moderate lung disease

Background: Airway inflammation due to chronic infection is the leading cause of respiratory failure and death in most of patients with cystic fibrosis (CF). There is some evidence about anti-inflammatory activity of phosphodiesterase inhibitors in adult patients with CF. This study was designed to evaluate the efficacy, safety, and tolerability of sildenafil (a phosphodiesterase inhibitor drug) in children with CF.

Method: This uncontrolled before-after study was conducted on 20 children with CF (mean age 14 ± 2.8 years, 50% male) with mild to moderate lung disease who were referred to CF clinic of Imam Hossein hospital in Isfahan, Iran. The patients received oral sildenafil (1 mg/kg p.o tid for 3 months). Changes in spirometric values, maximal exercise capacity, and patient-reported health by using the cystic fibrosis questionnaire-revised (CFQ-R) were evaluated before and after treatment.

Result: CFQ-R (69.54 ± 4.6 vs 76.90 ± 5.4; P < .001) and exercise duration (401 ± 45.6 vs 497 ± 60.1 second; P < .01) increased following sildenafil therapy. In contrast, the forced expiratory value (FEV_1; 84.60 ± 13.67 vs 78.40 ± 12.95; P < .001) and FEF25-75 (77.80 ± 27.33 vs 69.20 ± 21.91; P = .004) showed significant decreases. However, the mean of FEV₁ /forced vital capacity did not change significantly during the study (P = .682).

Conclusions: Although sildenafil can improve the quality of life and exercise capacities in CF children, it significantly decreases lung function. So, administration of this drug for CF children should be reconsidered.