DISPOSITION OF FOSCARNET DURING PERITONEAL-DIALYSIS

OBJECTIVE: To report the disposition of foscarnet in a patient undergo ing peritoneal dialysis, CASE SUMMARY: A 34-year-old man with AIDS rec eived foscarnet for the treatment of esophageal cytomegalovirus. We ch aracterized the clearance of foscarnet in this patient during continuo us cyclic peritoneal dialysis (CCPD) and continuous ambulatory periton eal dialysis (CAPD). DISCUSSION: The foscarnet half-lives during CCPD and CAPD were 41.4 and 45.8 hours, respectively. These values are sign ificantly greater than the half-life of 4.5 hours observed in patients with normal renal function and about half that reported in anuric pat ients undergoing hemodialysis during the interdialytic period, The CCP D and CAPD clearances of foscarnet were 5.8 and 4.5 mL/min, respective ly; the CAPD clearances of creatinine and urea nitrogen were 4.1 and 6 .0 mL/min, respectively. The patient's estimated total body clearance values of foscarnet during CCPD and CAPD were 9.8 and 8.8 mL/min, resp ectively, Thus, CCPD and CAPD augmented the patient's residual clearan ce of foscarnet by 145% and 105%, respectively, CONCLUSIONS: Since inc remental increases in residual clearance of 30% or more generally will result in clinically significant changes in a drug's serum concentrat ion, foscarnet dosage needs to be individualized for patients receivin g peritoneal dialysis.