Comparison of two durations of triple-drug therapy in patients with uncomplicated brucellosis: A randomized controlled trial.

Background: Brucellosis remains the most common zoonotic disease throughout the world and especially in Iran. Several clinical trials have tested different therapeutic regimens for brucellosis, but few have assessed the optimal duration of treatment.

Methods: We performed a randomized controlled trial to compare a triple-drug regimen of doxycycline plus rifampicin for 6 weeks and streptomycin for the first 7 days with doxycycline plus rifampicin for 8 weeks and streptomycin for 7 days in patients with uncomplicated brucellosis in Arak, Iran. The primary outcome measure for the treatment groups was the relapse rate measured at 1, 3, 6, 12, and 24 months after cessation of therapy.

Results: Eligible patients were randomized to one of the 2 groups with 72 per arm. We found no significant difference in the relapse rate for the 8-week treatment group compared to the 6-week group (9.7% vs 13.9%). There were no significant differences between the 6-week and 8-week groups regarding the relapse rate, period between clinical presentation and beginning of treatment, and time of relapse. Symptom resolution was achieved in all cases at a median 9.5 days and no cases experienced continuing symptoms after treatment.

Conclusions: Our trial found no significant difference between 6-week and 8-week regimens of doxycycline and rifampicin plus streptomycin for the first 7 days. Further comparative studies with a large sample size should be implemented to achieve a consistent therapeutic regimen for uncomplicated brucellosis, to help identify those who may benefit from longer treatment, and to minimize adverse effects and unnecessary continuation of treatment.