Decreased intraperitoneal insulin requirements during peritonitis on continuous ambulatory peritoneal dialysis

IntraperitonealInsulin: A Protocol for Administration during CAPD and Review of Published Protocols

For many diabetics in end-stage renal failure, the initial therapy they receive will be continuous ambulatory peritoneal dialysis (CAPD) together with i.p. insulin. To date, all published protocols rely on empirical dosages based upon predialysis insulin requirements. A practical regimen for the institution of i.p. insulin administration during CAPD is described. The only endpoints used to determine insulin dosage were fasting plasma glucose 5 to 10 mmol/L and 2 h postprandial plasma glucose 8 to 15 mmol/L. An initial protocol related to body weight, dextrose content, volume, and timing of dialysate was based on a retrospective analysis of the results in our first 10 patients. Subsequently, a prospective assessment in an additional 22 patients confirmed the effectiveness of the regimen. The following protocol is recommended for the institution of i.p. insulin therapy in patients undergoing CAPD: Preprandial exchanges 1.36% dextrose-0.175 U/L dialysate/kg body weight 3.86% dextrose-0.25 U/L/kg Overnight exchanges 1.36% dextrose-0.1 U/L/kg 3.86% dextrose-0.15 U/L/kg Further adjustment of insulin dosage is then made on the basis of four hourly plasma glucose profiles. Self-monitoring of capillary blood glucose is recommended.

Marked Variation in Peritoneal Insulin Absorption in Peritoneal Dialysis

Objective

To assess both peritoneal insulin absorption and adsorption of insulin to the plastic delivery system, and to assess whether variation in peritoneal absorption is related to transport status.

Design

Eight insulin-dependent diabetic patients on continuous ambulatory peritoneal dialysis were studied. Insulin was added to the dialysate. The amount adsorbed by the bag tubing was determined; peritoneal absorption was measured by complete spent dialysate collection.

Results

Only 14% ± 5% of added insulin was adsorbed onto the dialysate delivery system. Marked variation in peritoneal absorption occurred (38% ± 14%, range 17% – 66%). Variations in membrane transport status did not account for variation in absorption.

Conclusion

Marked variation in peritoneal absorption of insulin occurs, accounting for some of the variation in intraperitoneal insulin requirements. This is not related to membrane transport status.

Clinical pharmacokinetics during continuous ambulatory peritoneal dialysis

Peritoneal dialysis (PD) has gained recognition worldwide as an alternative to haemodialysis in the management of patients with end-stage renal disease. Because the peritoneal catheter provides direct access to the peritoneum, intraperitoneal drug administration has become widely used for the administration of certain drugs. The instillation and drainage of PD fluids contribute to the total body clearance of drugs given by other routes. For most drugs, peritoneal clearance is low. This paper provides an updated review of recently published pharmacokinetic studies involving the administration of selected drugs to patients receiving PD. Antibiotics continue to be extensively studied and administered in PD patients because of the frequent occurrence of infections. Epoetin (recombinant human erythropoietin) has become widely used and is the subject of ongoing pharmacokinetic investigation. Intraperitoneal insulin has become accepted for the treatment of patients with diabetes receiving PD; the pharmacokinetics of vitamin D analogues in PD patients continue to be explored.