Trimethoprim-sulfamethoxazole (SXT) versus azithromycin for the treatment of undifferentiated febrile illness in Nepal: a double-blind, randomized, placebo-controlled trial.

BACKGROUND Azithromycin and trimethoprim-sulfamethoxazole (SXT) are widely used to treat undifferentiated febrile illness (UFI). We hypothesized that azithromycin is superior to SXT for UFI treatment, but the drugs are non-inferior to each other for culture-confirmed enteric fever treatment. METHODS We conducted a double blind, randomized, placebo-controlled trial of azithromycin (20 mg/kg/day) or SXT (trimethoprim 10 mg/kg/day + sulfamethoxazole 50 mg/kg/day) orally for 7 days for UFI treatment in Nepal. We enrolled patients (aged 3-64 years) presenting to two Kathmandu hospitals with temperature ≥ 38.0°C for ≥4 days without localising signs. The primary endpoint was fever clearance time (FCT); secondary endpoints were treatment failure and adverse events. ClinicalTrials.gov number: NCT02773407. RESULTS From June 2016 to May 2019, we randomized 326 participants (163 in each arm); 87 (26.7%) had blood culture-confirmed enteric fever. In all participants, the median FCT was 2.7 days (95% CI 2.6-3.3) in the SXT arm and 2.1 days (95% CI 1.6-3.2) in the azithromycin arm 1.25 (95% CI 0.99-1.58, P=0.059). The hazard ratio of treatment failures by 28 days between azithromycin and SXT was 0.62 (95% CI 0.37-1.05, p=0.073). Planned sub-group analysis showed azithromycin resulted in faster FCT in those with sterile blood cultures and less relapses in culture-confirmed enteric fever. Nausea, vomiting, constipation, and headache were more common in the SXT arm. CONCLUSIONS Despite similar FCT and treatment failure in the two arms, significantly fewer complications and relapses make azithromycin a better choice for empirical treatment of UFI in Nepal.