List of products in the National Drug Code with proprietary name . Tolbutamide is used with a proper diet and exercise program to control high blood sugar in people with type 2 diabetes. It may also be used with other diabetes medications. Controlling high blood sugar helps prevent kidney damage, blindness, nerve problems, loss of limbs, and sexual function problems. Proper control of diabetes may also lessen your risk of a heart attack or stroke. Tolbutamide belongs to the class of drugs known as sulfonylureas. It works by causing the release of your body's natural insulin and may help to restore your body's proper response to insulin.