Rifampin does not improve the efficacy of quinolone antibacterial prophylaxis in neutropenic cancer patients: results of a randomized clinical trial.

Purpose: To determine whether the addition of rifampin to a quinolone-based antibacterial prophylactic regimen in patients undergoing high-dose chemotherapy (HDC) with peripheral-blood stem-cell transplantation (PBSCT) decreases the incidence of neutropenia and fever, Gram-positive bacteremia, and infection-related morbidity.

Patients And Methods: Patients with solid tumors undergoing HDC with PBSCT were randomized to receive prophylactic antibiotics with either ciprofloxacin 500 mg orally every 8 hours or the same ciprofloxacin regimen with rifampin 300 mg orally every 12 hours. Prophylaxis was started 48 hours before stem-cell reinfusion. Patients were monitored to document the occurrence of neutropenia and fever, incidence and cause of bacterial infection, time to onset and duration of fever, requirement for intravenous antimicrobials, and length of hospital admission.

Results: Sixty-five patients were randomized to receive ciprofloxacin and 65 to receive ciprofloxacin plus rifampin, and from these groups, 62 and 61 were assessable, respectively. The proportion of patients who developed neutropenia and fever was 87% in the group treated with ciprofloxacin and 78% in the group treated with ciprofloxacin and rifampin (P =.25). Although there was a trend toward a reduction in the overall incidence of bacteremia (12 v 4 patients), and Gram-positive bacteremia (8 v 2 patients) with the addition of rifampin, none of these comparisons was statistically significant (P =.05 and P =.09, respectively).

Conclusion: The results of this study, which demonstrate that rifampin does not improve ciprofloxacin antibacterial prophylaxis in cancer patients undergoing HDC with PBSCT support but that it does increase the occurrence of undesirable side effects, do not support the routine use of rifampin in this setting.