Optimized antibiotic plasma predictor efficacy is essential in systemic infections. The uricosuric agent probenecid inhibits tubular excretion of antibiotics and may be used as β-lactam pharmacokinetic enhancer (BLPKE), even though few data are currently available for this purpose.

We conducted a monocentric and retrospective observational study including all patients who received probenecid in combination with parenteral β-lactam antibiotics for systemic infections from Jan 1, 2014 to Dec 31, 2019. Demographics, infection characteristics, treatment and ATC (antibiotics trough concentration) were investigated.

All in all, 38 patients were included. Eight patients had a history of sickle cell disease. Hyperfiltration (defined as eGFR>130mL/min/1.73m²) was detected in twenty-one patients including six with sickle cell disease. Probenecid (500mg q6h orally) was added to antibiotics for a median (IQR) of 13 days (6.75–21.75), after a median (IQR) time lapse of 7 days (4–16) following the initiation of antibiotics. Probenecid was administered for low antibiotic trough concentration in 29 patients, for increased renal clearance in 5 patients and for persisting fever despite antibiotic therapy in 4 patients (including 1 infective relapse). A second plasma trough concentration, following probenecid administration, was available in 19 patients within a median (IQR) 3 days (2–5). Probenecid induced increased ATC in 18/19 patients (94.7%), with a median (IQR) change of +228.4% (IQR 38.7–633). No major adverse effects were reported.

Probenecid could be a BLPKE. Our data suggest this drug should be used more often to optimize β-lactam pharmacokinetics in clinical practice.