Influence of loxoprofen use on recovery from naturally acquired upper respiratory tract infections: A randomized controlled trial

Objective: To investigate whether loxoprofen, one of the nonsteroidal anti-inflammatory drugs, prolongs the recovery process of naturally acquired upper respiratory tract infections (URTIs) in the clinical setting. Methods: A double-blind, randomized, placebo-controlled trial was conducted in 23 outpatient facilities in Japan. Patients aged 18 through 65 years suffering from URTIs were randomly assigned to receive loxoprofen or its placebo. The primary outcome was duration of illness in days. Results: A total of 174 patients were available for the analyses. Duration of illness was 8.94 ± 3.20 days in the loxoprofen group compared to 8.39 ± 3.39 days in the placebo group (P=.19). The number of days with limited daily activities was fewer in the loxoprofen group than in the placebo group (2.12 ± 2.05 days vs. 2.68 ± 2.54 days, P=.17). Although severe symptoms were less frequent on days 1, 2, and 3 in the loxoprofen group (27%, 33%, and 29%, respectively) than in the placebo group (32%, 39%, and 37%, respectively), symptoms were more frequent on days 6 through 12 in the loxoprofen group (difference, 5-13%). Adverse events were more common in the loxoprofen group (9.5% vs. 1.1%, P=.051). Conclusion: Loxoprofen did not significantly modify the recovery process of URTIs except for a slight tendency to delay.