oral hypoglycemic agent

Abbreviation: OHA.
Any drug taken by mouth that lowers or maintains blood glucose (as opposed to insulin, a drug taken parenterally to control blood sugar). In addition to diet and exercise regimens, OHAs are typically used to control blood glucose levels in type 2 diabetes mellitus. Commonly used oral agents for diabetes include metformin (a biguanide), sulfonylureas (such as glyburide), alpha-glucosidase inhibitors (acarbose), and thiazolidinediones (pioglitazone). Used appropriately, OHAs lower hemoglobin A1c levels by about 0.5 to 1.5%. See: table * Combinations of these drugs, either with each other or with insulin, may be used in patients with poorly controlled diabetes mellitus.

Class of Drug	Activity	Adverse Features	Approximate Cost
Alpha-glucosidase inhibitors, e.g., acarbose	Delay absorption of glucose from intestinal tract	Flatulence and other abdominal side effects	Expensive
Biguanides, e.g., metformin	Improve sensitivity to insulin; decrease glucose production by the liver	Less weight gain than with other agents; avoid in patients with renal failure	Very expensive
Sulfonylureas, 1st generation, e.g., tolazamide	Cause beta cells to release insulin	Resistance to drug may develop over time	Inexpensive
Sulfonylureas, 2nd generation, e.g., glipizide, glyburide, others	Same as 1st generation; also increase sensitivity to insulin	Same as 1st generation	Moderately expensive
Thiazolidinediones, e.g., pioglitazone	Improve sensitivity to insulin; improve lipid profile	Monthly monitoring of liver functions needed for some drugs in this class due to risk of toxicity. Heart failure and other heart diseases.	Very expensive