The Peritoneal Handling of Digoxin during CAPD

We measured digoxin concentrations in serum and dialysate from five digitalized patients on continuous ambulatory peritoneal dialysis (CAPD). Mean peritoneal clearance of digoxin was 3.6 ± 0.4 ml/min (± SEM). Mean mass transfer was 8.6 ± 0.6 μg/min. Our patients lost from 3.7 to 13.3% of their daily oral digoxin intake in dialysate. The mean dialysate over serum (D/S) digoxin ratio was 0.59 and fell between D/S creatinine (0.81) and D/S inulin (0.34). Between patients the range of this ratio was wide (0.25 to 0.90). We also measured serial digoxin dialysate concentrations during a six hour “dwell” in one patient and determined a D/S equilibration curve. After six hours dialysate digoxin approached a plateau near 0.5. Digoxin removal per week from dialysate was two to three times greater during CAPD than that reported from IPD. Peritoneal losses of digo xin cannot be predicted for an individual patient. In four of eight digitalized patients, the cardiac drug could be discontinued suggesting a beneficial effect of long-term CAPD in controlling congestive heart failure.