Sulfonylureas – Diabetes Medicine Explanation & Overview

If you have type 1 diabetes[1], your pancreas no longer makes enough insulin[2]. Insulin is a hormone that helps glucose move from the bloodstream into your cells where the glucose is used for energy. Everyone who has type 1 diabetes must take insulin, whether by injection, inhalation (for rapid-acting insulin) or insulin pump, to survive. There is no “insulin pill,” at least at this time.

With type 2 diabetes[3], the situation is a bit different. In the early stages of type 2 diabetes, the body makes plenty of insulin, but has a hard time using it. This is called insulin resistance[4]. Certain medicines, such as metformin[5], can help improve insulin resistance so that the body can use insulin better. But as type 2 diabetes progresses, the pancreas can get tired and stop making enough insulin to keep up with the demand. If and when this happens, insulin injections are usually needed.


This week, we’ll look at another class of diabetes pills called sulfonylureas.

What are sulfonylureas?

One of the trickiest drug names to pronounce, sulfonylureas (SUL-fah-nil-YOO-ree-ahs[6]) are the oldest type of diabetes pills available. They were developed in the 1940s and were the first type of diabetes pill to enter the market.

These pills, which are sometimes called “oral hypoglycemic agents,” work very differently than metformin. They signal the pancreas to release insulin and they also help the body’s cells use insulin better. Sulfonylureas may be old, but they’re effective: They can lower A1C[7] levels (a measure of blood sugar control over the previous two to three months) by 1% to 2%.

Sulfonylureas list

There are two generations of sulfonylureas: first and second. The first-generation drugs include the following:

• tolbutamide (brand name Orinase)

• tolazamide (Tolinase)

• chlorpropamide (Diabinese)

The second-generation drugs, which are more commonly used these days, include the following:

• glimepiride (Amaryl)

• glipizide (Glucotrol and Glucotrol XL)

• glyburide (Diabeta, Micronase, and Glynase)

Sulfonylureas are often taken with other types of diabetes medicines, such as metformin and insulin. They’re also available as combination pills; for example, combined with metformin (Metaglip).

How are sulfonylureas taken?

Sulfonylureas are tablets that are taken anywhere from once a day to twice a day. Each type of sulfonylurea is available in different dosages or strengths. In general, your doctor will start you off on the lowest dose and gradually increase the dose, as needed, until your blood sugars come into target range.

Sulfonylureas side effects

The most common and serious side effect of these drugs is low blood sugar (hypoglycemia[8]). To avoid this, it’s important that you not skip meals when taking these medicines. Another possible side effect is weight gain, likely due to increased insulin secretion. Less common side effects include a skin rash and stomach upset.

Sulfonylureas may not be safe for people who have liver or kidney problems[9]. One of the drugs in this class, glyburide, may be safe for pregnant women with diabetes who choose not to take insulin; however, sulfonylureas are not deemed safe for nursing women.

What else should you know about sulfonylureas?

Sulfonylureas are very effective, but as with all medicines, there are pros and cons to taking them.

Up to 20% of people who take these drugs won’t respond to them; in other words, they won’t help to significantly lower blood sugar levels. For some other people, these drugs may work initially, but over time, they’ll become less effective.

It’s important to check your blood sugar levels regularly when taking a sulfonylurea.

Make sure you know the signs and symptoms of low blood sugar (dizziness, lightheadedness, shakiness, sweating, headache, hunger) and how to treat it (take 15 grams of carbohydrate, such as 3–4 glucose tablets, a tube of glucose gel, or 4 ounces of juice; wait 15 minutes to recheck your blood sugar, and treat again if it is still low).

If you are having frequent low blood sugars, let your doctor know; you may need a lower dose.

Your skin may be more sensitive to sunlight while on these drugs. Be sure to use adequate sun protection.

Want to learn more about the role of medicines in treating diabetes? Read the rest of diabetes educator Amy Campbell’s eight-part series on diabetes drugs, covering metformin[5], meglitinides[10], thiazolidinediones[11], DPP-4 inhibitors[12], SGLT2 inhibitors[13], alpha-glucosidase inhibitors[14], bile acid sequestrants and dopamine receptor agonists[15], non-insulin injectable diabetes medications[16], and insulin[17].

  1. type 1 diabetes:
  2. insulin:
  3. type 2 diabetes:
  4. insulin resistance:
  5. metformin:
  6. SUL-fah-nil-YOO-ree-ahs:
  7. A1C:
  8. hypoglycemia:
  9. kidney problems:
  10. meglitinides:
  11. thiazolidinediones:
  12. DPP-4 inhibitors:
  13. SGLT2 inhibitors:
  14. alpha-glucosidase inhibitors:
  15. bile acid sequestrants and dopamine receptor agonists:
  16. non-insulin injectable diabetes medications:
  17. insulin:

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Amy Campbell: Amy Campbell is the author of Staying Healthy with Diabetes: Nutrition and Meal Planning and a frequent contributor to Diabetes Self-Management and Diabetes & You. She has co-authored several books, including the The Joslin Guide to Diabetes and the American Diabetes Association’s 16 Myths of a “Diabetic Diet,” for which she received a Will Solimene Award of Excellence in Medical Communication and a National Health Information Award in 2000. Amy also developed menus for Fit Not Fat at Forty Plus and co-authored Eat Carbs, Lose Weight with fitness expert Denise Austin. Amy earned a bachelor’s degree in nutrition from Simmons College and a master’s degree in nutrition education from Boston University. In addition to being a Registered Dietitian, she is a Certified Diabetes Educator and a member of the American Dietetic Association, the American Diabetes Association, and the American Association of Diabetes Educators. Amy was formerly a Diabetes and Nutrition Educator at Joslin Diabetes Center, where she was responsible for the development, implementation, and evaluation of disease management programs, including clinical guideline and educational material development, and the development, testing, and implementation of disease management applications. She is currently the Director of Clinical Education Content Development and Training at Good Measures. Amy has developed and conducted training sessions for various disease and case management programs and is a frequent presenter at disease management events.

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