Side effects of sulfonylureas

What Are Sulfonylureas?

This class of drugs can be an important part of a type 2 diabetes treatment plan.

Sulfonylureas are a group of medicines used to treat type 2 diabetes.

With type 2 diabetes, the body doesn’t use the hormone insulin properly, leading to elevated levels of blood sugar (glucose).

The first sulfonylureas were developed in the 1950s.

The drugs work by increasing the release of insulin from the pancreas.

Sulfonylureas are only one part of a treatment plan for type 2 diabetes, which should also include diet and exercise to help control blood sugar levels.

Taking sulfonylureas, along with adopting a healthy lifestyle, can reduce your risk of developing serious or life-threatening complications of diabetes, which may include heart disease, stroke, nerve damage, kidney problems, or eye problems.

Common Sulfonylureas

Some commonly prescribed sulfonylureas include:

  • DiaBeta, Glynase, or Micronase (glyburide or glibenclamide)
  • Amaryl (glimepiride)
  • Diabinese (chlorpropamide)
  • Glucotrol (glipizide)
  • Tolinase (tolazamide)
  • Tolbutamide

Sulfonylureas are often taken in combination with other medicines, especially the drug metformin.

Side Effects of Sulfonylureas

Side effects of sulfonylureas may include:

  • Signs of low blood sugar, such as sweating, dizziness, confusion, or nervousness
  • Hunger
  • Weight gain
  • Skin reactions
  • Upset stomach
  • Dark-colored urine

Sulfonylurea Precautions

Sulfonylureas shouldn’t be taken by people with type 1 diabetes or diabetic ketoacidosis (a dangerous condition that can occur if high blood sugar is left untreated).

People with liver or kidney problems may not be able to take sulfonylureas. Talk to your doctor if this is a concern.

Some sulfonylureas may make your skin more sensitive to sunlight. Avoid unnecessary exposure to the sun, and wear sunscreen and protective clothing while outdoors.

Sulfonylureas typically cause changes in your blood sugar levels. You should know the symptoms of high and low blood sugar, and what to do if you experience them.

Some oral diabetes drugs may increase your risk of serious heart problems.

Not treating your diabetes can damage your heart and other organs. Talk to your doctor about these risks.

Your doctor will probably want to check your blood sugar and urine sugar levels often while you’re taking a sulfonylurea. Keep all appointments with your doctor’s office and laboratory.

Consider wearing a diabetic ID bracelet to be sure you get proper treatment in case of an emergency.

Let your healthcare provider know you’re taking a sulfonylurea before having any type of medical procedure, including a dental procedure.

Tell your doctor about all prescription, non-prescription, illegal, recreational, herbal, nutritional, or dietary drugs you’re taking before starting on a sulfonylurea.

Sulfonylureas and Alcohol

Alcohol may worsen certain side effects of sulfonylureas.

Limit or avoid drinking alcohol while taking these medicines.

Sulfonylureas and Pregnancy

Tell your doctor if you’re pregnant or might become pregnant while taking a sulfonylurea.

It’s not known whether these drugs are safe to use during pregnancy.

Also, talk to your healthcare provider before taking sulfonylureas if you’re breastfeeding.

If you have Type 1 diabetes, your pancreas no longer makes enough insulin. 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, 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. Certain medicines, such as metformin, 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) are the oldest type of diabetes pills available. They were developed in the 1940’s 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 levels (a measure of blood sugar control over the previous 2–3 months) by 1% to 2%.

There are two generations of sulfonylureas: first and second. The first-generation drugs include tolbutamide (brand name Orinase), tolazamide (Tolinase), and chlorpropamide (Diabinese). The second-generation drugs, which are more commonly used these days, include glimepiride (Amaryl), glipizide (Glucotrol and Glucotrol XL), and 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.

What are the side effects of sulfonylureas?
The most common and serious side effect of these drugs is low blood sugar (hypoglycemia). 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. 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.

What underappreciated hormone can save you from severe low blood sugar? Bookmark and tune in tomorrow to find out!

About the author

Leave a Reply

Your email address will not be published. Required fields are marked *