Effects of Glipizide and Food Intake on the Blood Levels of Glucose and Insulin in Diabetic Patients

The blood levels of glucose and insulin were monitored in 15 patients with non‐ketotic maturity‐onset diabetes mellitus given a single 5 mg oral dose of a novel sulfonylurea drug, glipizide, together with, and 30 min prior to, a standardized breakfast meal. In addition, the effect of the meal only was examined. The mean preprandial levels of blood glucose and plasma insulin on the three occasions were similar. Following glipizide administration, the early postprandial increment of blood glucose was reduced, and there was a subsequent decrease to values below the preprandial level. Both the decrease and the reduction of the early increase were significantly more marked when the drug was given 30 min prior to than together with the meal. Apparently, this did not result from a stronger effect of the drug on insulin release when given before than together with the meal, as the plasma insulin levels and the corresponding concentration curve areas did not differ. Rather, the difference was due to a more optimal timing between insulin release and the blood glucose increment evoked by the meal. In addition, there seemed to be only a minor interindividual variation in the bioavailability of the drug, as its effect on insulin levels varied rather little. Hence, 5 mg of glipizide three times daily 30 min before meals can be recommended as a standard regimen.