Issue 139 Item 8 Glipizide Controls Postbreakfast Hyperglycemia

Nateglinide better suited to patients with isolated postprandial hyperglycemia or those with very irregular eating habits. When given at the recommended premeal time, glipizide is as effective as nateglinide in controlling postbreakfast hyperglycemia in patients with type 2 diabetes, according to a report in the December issue of Diabetes Care.

Nateglinide has been shown to restore the decrease in early postprandial insulin secretion that leads to postprandial hyperglycemia, the authors explain, and previous studies suggested that glipizide could normalize early insulin release and reduce postprandial hyperglycemia. No studies, however, have compared the acute premeal administration of these two agents in controlling postprandial hyperglycemia in type 2 diabetics.

Dr. Mary F. Carroll, and colleagues from the University of New Mexico Health Sciences Center in Albuquerque, compared the effectiveness of acute premeal administration of glipizide and nateglinide (both given as recommended in the package insert) in controlling hyperglycemia after breakfast in a crossover study of 20 patients with type 2 diabetes.

Postprandial glucose profiles did not differ significantly after treatment with glipizide, nateglinide, or glipizide plus nateglinide, the authors report.

Plasma glucose levels 4 hours after eating were significantly lower after glipizide or glipizide-plus-nateglinide treatment than after placebo or nateglinide treatment, the results indicate, and had returned to fasting levels.

Peak levels of insulin and excursions of insulin levels were higher with glipizide than with nateglinide or placebo, the researchers note, but integrated insulin levels and insulin levels at 30 minutes postmeal were similarly elevated for both oral hypoglycemics.

C-peptide changes postmeal paralleled those seen in insulin levels, the report indicates, reflecting pancreatic release of insulin rather than altered metabolism.

Dr. Carroll, at Eastern New Mexico Medical Center in Roswell, New Mexico stated "Generic glipizide is equivalent to nateglinide in the control of postbreakfast hyperglycemia. "Of the two agents", most patients with type 2 diabetes requiring oral hypoglycemic agents would do better with glipizide."

"Nateglinide may be better suited to patients with isolated postprandial hyperglycemia (normal fasting blood glucose levels) or perhaps those with very irregular eating habits," Dr. Carroll added.

"The timing of glucose lowering agents in relation to meals may be very important in optimizing the efficacy of which ever agent is used," Dr. Carroll concluded. Diabetes Care 2002;25:2147-2152.