Pharmacokinetics of Amoxicillin and Cefepime During Prolonged Intermittent Renal Replacement Therapy: A Case Report

Prolonged intermittent renal replacement therapy (PIRRT) is an emerging form of renal replacement therapy in critically ill patients, but dosing data for antibiotics such as amoxicillin and cefepime are scarce and limited. This case report describes the effect of PIRRT on the plasma pharmacokinetics of amoxicillin and cefepime in a 69-year-old, critically ill patient with a polymicrobial intra-abdominal infection. Blood samples taken over 2 days, including a 7-hour PIRRT session, were analysed and a two-compartment model was used to describe cefepime and amoxicillin clearance and dosing requirements during PIRRT and off-PIRRT in this patient. Based on these data, an off-PIRRT dose of 1 g amoxicillin 12-hourly and cefepime 2 g daily with an on-PIRRT dose of 1 g amoxicillin 8-hourly and cefepime 2 g 12-hourly was deemed appropriate.