Optimal time of administration of insulin lispro. Importance of meal composition

To compare the glucodynamics of pre- and postprandial administration of insulin lispro using test meals of differing composition.

Twenty subjects with IDDM were studied on four separate occasions. Ten subjects ingested high-carbohydrate and high-fat breakfasts with a large liquid component, and 10 subjects ingested high-carbohydrate and high-fat breakfasts in a more solid form. With each meal, insulin lispro was injected 10 min preprandial on one occasion and 20 min postprandial on another. The magnitude and temporal pattern of postprandial glucose excursions were observed.

With all meal types studied, postprandial blood glucose excursions were significantly smaller when insulin lispro was administered preprandially (P < 0.05). With both high-carbohydrate meals and the liquid high-fat meal, preprandial administration of lispro was associated with modest postprandial increments of blood glucose. With the solid high-fat meal, preprandial lispro produced a cumulative decline in postprandial blood glucose, whereas blood glucose rose when lispro was administered postprandially.

For meals with a high carbohydrate content, the optimal time of administration of lispro is preprandial. However, for meals with a high solid fat content, postprandial administration of lispro may be preferable.