Obesity not a reason for aggressive levofloxacin dosing for febrile neutropaenia prophylaxis

Obesity does not appear to be strongly correlated with an increased risk for febrile neutropaenia during levofloxacin prophylaxis in patients with haematological malignancies receiving intermediate-risk myelosuppressive chemotherapy, suggests a study.

“Levofloxacin given at a standard dose of 500 mg daily is recommended for antibacterial prophylaxis in patients receiving myelosuppressive chemotherapy,” the investigators said. “Obese patients have been shown to exhibit enhanced clearance of levofloxacin and may be at risk for prophylactic failure.”

To test this hypothesis, a single-centre, retrospective cohort study was conducted from June 2014 to May 2017, evaluating adult patients with estimated creatinine clearance ≥50 mL/min receiving their first cycle of a National Comprehensive Cancer Network defined intermediate-risk regimen.

The incidence of febrile neutropaenia was the primary outcome, while 30-day mortality and the correlation between estimated levofloxacin area under the concentration–time curve and rates of febrile neutropaenia were the secondary outcomes.

Twenty-six patients developed febrile neutropaenia: 12 (35.3 percent) obese and 14 (21.9 percent) nonobese (p=0.16). Of these, six (23.1 percent) required intensive care. No deaths were recorded within 30 days of a febrile neutropaenia event.

Obese and nonobese patients showed comparable estimated creatinine clearance (median, 97.5 vs 91.8 mL/min; p=0.39), as well as estimated levofloxacin area under the concentration–time curve (median, 85.6 vs 90.8 mg×h/L; p=0.39).

No significant associations were found between body weight-related variables—total body weight (median, 83.4 vs 80.6 kg; p=0.51), body mass index (mean 29.6 vs 26.8 kg/m²; p=0.35), or body surface area (1.98 vs 1.99 m²; p=0.68)—and febrile neutropaenia in this cohort of patients with similar renal function.