asthma in 2019 in Iran. For case group, was prescribed sildenafil (50 mg) daily and the
control group received the placebo. In the beginning of the study and one month later,
volume parameters, 6-minute walk distance (6MWD), and the quality-of-life questionnaire
were measured and compared in the two groups. Results: Twenty patients were entered into
this study. 8 patients (40%) were male and 12 (60%) were female. The results showed that …