Drug Comparisons

Being the first category of oral drugs used to treat Type 2 Diabetes, the sulfonylureas were the only blood sugar-lowering medications available in the United States until 1995. Sulfonylureas can be further classified into two groups or "generations" based on their potency, duration of action, and drug interactions/side effects profiles.

All drugs in the sulfonylurea class work in the same way to lower blood sugar. The drugs do this by stimulating secretion of insulin from the pancreas, increasing the body's sensitivity or response to insulin, and reducing the release of sugar from the liver.

Drugs in this Class
Chlorpropamide Tablets ( Chlorpropamide, Diabinese )
Glimepiride Tablets ( Amaryl Tablets )
Glipizide Extended-Release Tablets ( Glipizide XL Extended-Release Tablets, Glucotrol XL Extended-Release Tablets )
Glipizide Tablets ( Glucotrol Tablets )
Glyburide Tablets ( Diabeta Tablets, Micronase Tablets )
Tolazamide
Tolbutamide

Summarizing the Evidence

• All drugs in this class are similarly effective in lowering blood sugar and HbA1C ("hemoglobin-A-1-C," a blood test used to measure long-term diabetes control) and are indicated for single therapy or for use in combination with other oral blood sugar-lowering drugs or insulin.

• First-generation sulfonylureas include acetohexamide (Dymelor), chlorpropamide (Diabinese), tolazamide (Tolinase), and tolbutamide (Orinase). These drugs are not as commonly prescribed any more because the newer second-generation sulfonylureas offer advantages in side effect profiles and have less drug interactions.

• Second-generation sulfonylureas include glimepiride (Amaryl), glipizide (Glucotrol), Glipizide ER (Glucotrol XL), and glyburide (Diabeta, Glynase, Micronase). These drugs are all similarly effective in lowering blood sugar levels; the maximal blood sugar-lowering capability of all second-generation sulfonylureas is comparable. Some minor differences do exist between the second-generation sulfonylureas. Glipizide produces a more rapid lowering of blood sugar compared to glyburide. However, glyburide is more potent than glipizide (meaning that lower doses of glyburide are generally needed compared to glipizide). Glimepiride and glipizide ER are longer acting (meaning they can generally be taken once daily instead of twice daily like glyburide and regular glipizide).

• Since all of the drugs in this class (both first and second generation) are available generically and are similarly effective for lowering blood sugar levels, the choice of which to use will generally depend on your doctor's preference, your prescription benefits formulary, and any concurrent medications that you may be taking (to avoid drug interactions).

• The American Diabetes Association (ADA), in their Clinical Practice Guidelines, recommend sulfonylureas as first-line drugs for the treatment of Type 2 diabetes. However, the ADA does not recommend one sulfonylurea over the other.

Dosing and Administration

• Glimepiride (Amaryl) and glipizide ER (Glucotrol XL) are generally taken once daily. All other sulfonylureas are typically taken once or twice daily.

Generic Availability

• All sulfonylureas are available generically.

Drug Interactions

Some interactions between medications can be more severe than others. The best way for you to avoid harmful interactions is to tell your doctor and/or pharmacist what medications you are currently taking, including any over-the-counter products, vitamins, and herbals. For specific information on how the drugs interact and the severity of the interaction, please use our Drug Interactions Checker.

Side Effects

To view specific side effect information, please use our Side Effect Checker.

Additional Information

References

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Last Updated: December 2007
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