Final answer:
The medication that has an antagonistic effect on insulin from the options provided is prednisone. It increases blood glucose levels and contrasts with the blood-glucose-lowering effect of insulin, making it an antagonist to insulin in patients with insulin-dependent diabetes mellitus.
Step-by-step explanation:
The patient in question has been diagnosed with insulin-dependent diabetes mellitus (IDDM, also known as type 1 diabetes). In IDDM, the primary issue is an absolute deficiency of insulin due to the destruction of pancreatic beta cells. The treatment for this form of diabetes includes administering insulin to manage blood glucose levels.
With regard to the medications listed, prednisone and glucagon are known to have antagonistic effects on insulin. Prednisone, a glucocorticoid, can increase glucose levels by stimulating gluconeogenesis and reducing peripheral glucose uptake. Glucagon, on the other hand, is a hormone produced by the alpha cells of the pancreas that raises blood glucose levels by promoting glycogen breakdown and gluconeogenesis in the liver.
Metformin and Glipizide are hypoglycemic agents used to treat type 2 diabetes. Metformin works by decreasing hepatic glucose production and increasing insulin sensitivity, while glipizide stimulates the release of insulin from pancreatic beta cells. Therefore, they do not have an antagonistic effect on insulin. From the options given, C. Prednisone is the correct answer as it has an antagonistic effect on insulin.