Managing Diabetic Patients who have Renal Failure. Part 4

Patient-Specific Considerations

Acute Renal Failure: Although reported infrequently, the diabetic patient in acute renal failure may also experience changes in insulin requirements and should be carefully monitored. In 1978 Weinrauch et al. described the development of acute renal failure in 12 insulin-dependent diabetes mellitus (IDDM) patients who received radiographic contrast material for a cardiac catherization. All of these patients had chronic renal insufficiency at baseline. Eleven of these patients demonstrated a need for less insulin during their acute renal failure. Eight of the 12 patients experienced a hypoglycemic reaction. In a case report described by Naschitz et al., a diabetic patient went into acute renal failure secondary to post – streptococcal glomerulonephritis. While in acute renal failure, the authors noted that the patient’s insulin requirements decreased from 56 to eight units daily. Subsequently, as the patient’s renal function improved, his insulin requirements increased. Although not relevant to this patient, other considerations to keep in mind when monitoring the diabetic patient with acute renal failure would include the patient’s daily caloric intake and the occurrence of emesis.

Pharmaceutical Care Decision Making Pharmacologic Agents: As described earlier, uremia may affect insulin activity and the ability of a patient to maintain optimal glucose control. The selection of the oral pharmacologic agents used to control blood glucose must also be evaluated. Prolonged half-lives of the agents or their metabolites and the potential for adverse drug events with the accumulation of these agents in renal failure are two key issues to consider. Chlorpropamide is a first-generation sulfonylurea. However, its use in patients with renal insufficiency should be avoided. It has a half-life of 24 – 48 hours, which is significantly increased with renal failure. This leads to the potential for a severe hypoglycemic reaction. Also, chlorpropamide use has been associated with hyponatremia and water retention.

Glyburide is a second-generation sulfonylurea that has a relatively long half-life. Approximately 50% of glyburide is excreted unchanged in the urine. It also has metabolites with hypoglycemic activity. It too has been associated with causing hypoglycemic reactions in patients with renal failure and its use should be avoided in patients with renal insufficiency.

Glipizide is another second-generation sulfonylurea. However, unlike glyburide, glipizide is cleared more quickly and its metabolites are inactive. The dose does not have to be decreased in renal insufficiency and thus is safe to use in diabetic patients with renal failure. Concerns associated with the use of the other oral sulfonylureas are described in Table 3.