No significant differences were observed in quality-of-life measures or the use of rescue medication ; however , the percentage of patients who used rescue medication was consistently lower in the lubiprostone group than in the placebo group at months 1 ( 34.9 vs. 37.7 % ) , 2 ( 23.4 vs. 26.6 % ) , and 3 ( 20.5 vs. 22.0 % ) .