Are there concerns with intermittent IP antibiotic dosing for peritonitis?
The goal of treating peritonitis is to ensure that a consistent MIC of antibiotics is maintained in the PD fluid. This prevents inadequate treatment, relapsing and repeat peritonitis, and development of microbial resistance. The principle behind intermittent IP antibiotic therapy is that antibiotics allowed to dwell in the peritoneal cavity for a period of at least 6 hours are absorbed into the bloodstream, where their volume of distribution serves as an “antibiotic depot.” Antibiotics from this systemic depot then move down their concentration gradient from the blood into the peritoneum during subsequent PD exchanges, which are devoid of added antibiotics. Achieving an MIC in those exchanges depends on the blood antibiotic concentration, the length of the exchange, and the rapidity of clearance of the systemic antibiotic depot. The latter may be augmented with more frequent exchanges, fast membrane transport status, and greater levels of RKF. Given these issues, there is a risk of suboptimal dosing and treatment when intermittent antibiotic therapy is used, particularly in APD. As such, antimicrobial therapy should be carefully thought out and individualized.