Samuel Grossman, BS Pharm, Pharm.D, CDE Answered 5/22/2015

Glipizide actually causes weight gain because it increases the release of insulin in some individuals. Based on the information that you provided, your friend may be losing weight due to poorly controlled diabetes. When Glipizide is not able to provide good glycemic control, sugar stays in the blood and cannot be utilized by the muscles for energy. The alternative source for fuel is fat and use of fat may cause weight loss. The problem with using fat for fuel is that a byproduct of fat metabolism is formation of ketones and can cause many complications. Please advise your friend to consult with his provider with regard to improving glycemic control and have him evaluated to make sure his weight loss will not put your friend in danger for complications.