What are the recommended antibiotic regimens for treating brucellosis in adults, and how long should treatment typically last?

Recommended antibiotic regimens for treating brucellosis in adults typically involve combination therapy to prevent relapse and ensure eradication of the infection. The most commonly recommended regimen is oral doxycycline combined with rifampicin. Doxycycline is usually given at 100 mg twice daily, and rifampicin at 600–900 mg once daily, both for a duration of at least 6 weeks. This combination is preferred due to its efficacy and ability to reduce relapse rates.

Alternative regimens include doxycycline combined with streptomycin, where streptomycin is administered intramuscularly for the first 2–3 weeks, but this is less commonly used in primary care settings.

Recent randomized controlled trials have compared different durations and combinations, suggesting that triple-drug therapy (e.g., doxycycline, rifampicin, and an additional agent like ciprofloxacin) may be effective, but the standard remains doxycycline plus rifampicin for 6 weeks in uncomplicated cases.

Typical duration of treatment is generally 6 weeks for uncomplicated brucellosis. Longer durations may be required for complicated cases such as neurobrucellosis or osteoarticular involvement, where treatment can extend to 8–12 weeks or more, often guided by specialist advice.

In summary, the first-line treatment for adult brucellosis is oral doxycycline 100 mg twice daily plus rifampicin 600–900 mg once daily for at least 6 weeks, with adjustments based on clinical response and complications (Agalar et al., 1999; Sofian et al., 2014; Tajerian et al., 2024).