EFFECT OF AN ORALLY-ADMINISTERED SULFONYLUREA, GLIPIZIDE, FOR TREATMENT OF DIABETES-MELLITUS IN CATS

An orally administered sulfonylurea drug, glipizide, was evaluated for treatment of diabetes mellitus. Confirmation of diabetes was based on evidence of appropriate clinical signs, persistent hyperglycemia, and glucosuria. Glipizide (5 mg, PO, q 12 h) was administered to each cat . Sixteen cats were fed a commercial high-fiber diet and 4 cats were f ed a commercial low-fiber diet. Insulin was not administered to any ca t during the study. Each cat was evaluated 2, 4, 8, and 12 weeks after initiation of treatment. Three clinical responses to glipizide treatm ent were identified. Mean preprandial blood glucose concentration and mean blood glucose concentration during an 8-hour postprandial period decreased to < 200 mg/dl in 5 of 20 (25%) cats. In these 5 cats, gluco suria was no longer detected and clinical signs resolved by the 4-week reevaluation. Euglycemia was maintained after discontinuing glipizide treatment in 2 of these 5 cats. Glycemic control has been maintained in 2 of 5 of the responding cats for 5 and 7 months of glipizide treat ment. One of 5 of the responding cats developed insulin-requiring diab etes mellitus after 6 months of glipizide treatment. Seven of 20 (35%) cats failed to respond to treatment. Mean preprandial blood glucose c oncentration and mean blood glucose concentration during an 8-hour pos tprandial period did not change from pretreatment values after 2 +/- 1 months; glucosuria persisted and clinical signs progressively worsene d. Insulin treatment was required to establish glycemic control in the se 7 cats. Eight of 20 (40%) cats partially responded to glipizide tre atment. Clinical signs and abnormalities identified on physical examin ation improved, and mean preprandial blood glucose concentration and m ean blood glucose concentration during an 8-hour postprandial period d ecreased by 146 +/- 105 and 110 +/- 50 mg/dl, respectively, at the 12 week reevaluation, compared with pretreatment values, but blood glucos e concentrations remained > 200 mg/dl and glucosuria persisted. These cats were treated with glipizide for a mean of 12 months (range, 7 to 21 months). Adverse reactions to treatment included vomiting shortly a fter administration of glipizide (3 cats), hypoglycemia (3 cats), and increased serum hepatic enzyme activities (3 cats). Retrospective anal ysis of information obtained from the 20 cats at the time of entry int o the study failed to identify any consistent factor that could be use d to predict the cats' response to glipizide treatment. Results of the study indicated that glipizide may be a viable alternative to insulin for treatment of diabetes mellitus in some cats.