Treatment of human brucellosis with doxycycline and gentamicin.

The objective of the present prospective, noncomparative, multicenter study was assess the safety and efficacy of gentamicin and doxycycline therapy for human brucellosis. In the first part of the study, a cohort of 17 patients received 100 mg of doxycycline (or 50 mg/kg of body weight per day if the body weight was < 40 kg) orally every 12 h for 45 days (cohort 1). In the second part of the study a subsequent cohort of 35 patients was treated with doxycycline at the same dosage for 30 days (cohort 2). All patients were treated intramuscularly with gentamicin at 240 mg (or 5 mg/kg per day if the body weight was < 50 kg) once daily for the first 7 days. Both cohorts showed a favorable response during therapy, and there were no therapeutic failures. Relapse was noted in 1 (5.9%; 95% confidence interval [95% CI], 0.15 to 28.7%) of the 17 patients in cohort 1 and in 8 (22.9%; 95% CI, 10.4 to 40.1%) of the 35 patients in cohort 2. Nineteen patients (36.5%; 95% CI, 23.6 to 51.0%) had adverse effects, with no differences between cohorts, and no patients had a treatment-limiting adverse effect. The study indicates that the combination of doxycycline for 45 days and gentamicin for 7 days is an effective and well-tolerated therapy for human brucellosis. The relapse rates obtained with doxycycline treatment for 30 days appear to be higher than those obtained with doxycycline treatment for 45 days.