Appropriate drug dosing in patients receiving peritoneal dialysis

The quantity of drugs removed during peritoneal dialysis is substantially lower than that during hemodialysis, and thus, the supplemental administration of drugs, even when they are efficiently removed during hemodialysis, is not necessary in patients receiving continuous ambulatory peritoneal dialysis (CAPD). However, because CAPD is a continuous hemocatharsis procedure, the cumulative removal of renally excretable drugs is higher in CAPD patients than in hemodialysis patients between sessions. Therefore, the weekly dosage of a drug can be approximately the same in CAPD patients and hemodialysis patients, and dosing design for patients with a pre-end-stage renal disease in the period prior to the initiation of dialysis can be applied to CAPD patients. Nevertheless, an appropriate dosage regimen, based on drug clearance, should be determined, because drug clearance is enhanced in patients receiving automated peritoneal dialysis, compared with those receiving CAPD, and also in those with urine output, compared to anuric patients. In addition, when residual renal function is impaired in CAPD patients with urine output, the decreased drug clearance must be compensated for by introducing a weekly hemodialysis treatment in some cases. Thus, careful consideration should be exercised in cases where drugs that have adverse effects on renal function are being administered, such as drugs that exert nephrotoxic effects and cause renal ischemia in CAPD patients. In the case of CAPD-related peritonitis, when an antibiotic that binds strongly to a protein is intravenously injected, the drug concentration in the peritoneal dialysate is low because only the unbound drug can be transported to the peritoneal dialysate. For this reason, when drugs, such as teicoplanin, that bind strongly to a protein are administered to CAPD patients with peritonitis, an intraperitoneal route is preferable to an intravenous route.