Sulfonylureas are a group of medications used to treat type 2 diabetes. They are not only inexpensive, but also the oldest oral anti-diabetes medications.
They are often used with metformin, sometimes along with other diabetes medications.
In this article, we’ll cover some general information about the drugs, including their examples, side effects, and who shouldn’t take them.
How do sulfonylureas lower blood sugar?
Insulin is the hormone that signals your body’s cells to take up and use glucose for energy, thereby reducing blood sugar levels. Sulfonylureas aid this process by:
- Increasing the amount of insulin produced by your pancreas.
- Limiting insulin breakdown in your liver.
- Making your cells more sensitive to insulin in the blood.
What are the types of sulfonylureas?
They are divided into 2 main classes:
II. First-generation sulfonylureas
They include drugs like chlorpropamide and tolbutamide. Due to concerns about serious side effects, their use was discontinued in the U.S. and they are rarely used in other countries where they are available.
II. Second generation sulfonylureas
They include:
- Glyburide, also called glibenclamide (Diabeta, Glynase)
- Glipizide (Minodiab, Glucotrol)
- Glimepiride (Amaryl)
- Gliclazide (Diamicron). It is not approved for use in the U.S. but is available in Canada, the UK, EU countries, and many others.
Are sulfonylureas safe for everyone?
No, they aren’t. Your doctor may choose to withhold these medications if you:
- Have liver disease
- Have kidney disease
- Are pregnant or breastfeeding
- Have diabetic ketoacidosis (DKA)
- Have acute porphyria or glucose-6-phosphate dehydrogenase deficiency. These are rare genetic conditions.
- Have previously had an allergic reaction to a sulfonylurea
What are the side effects of sulfonylureas?
Problems you might notice while on these drugs are:
- Low blood sugar (hypoglycemia)
- Weight gain
- Nausea
- Vomiting
- Flatulence (passing gas)
- Headache
- Diarrhea
- Dizziness
- Photosensitivity
- Features of an allergic reaction, like skin rash, itching, swelling of the face, lips, or throat.
What medications can interact with sulfonylureas?
Certain medications can increase your risk of sulfonylurea-induced hypoglycemia or affect their glucose-lowering effect. Some common ones include:
- Aspirin
- Cimetidine
- Ketoconazole
- Warfarin
- Some blood pressure drugs
- Birth control pills
- Corticosteroids
- Phenytoin
- Rifampin
- Sulfa-containing antibiotics
In addition to medications, alcohol can increase your risk of hypoglycemia when taken with sulfonylureas. In some people, this may also cause redness in the face, headache, and abdominal pain.
How to take sulfonylureas safely and effectively
To ensure safe usage, read the information leaflet that comes with your medication and adhere to the directions of the doctor or pharmacist.
You will take your medication once or twice a day, usually with meals. Take it at the same time every day.
When you miss a dose, take it as soon as you remember. If it’s almost time for your next dose, skip the missed dose and take the next dose as usual. Don’t take double doses to make up for missed ones.
While on sulfonylureas, you still need to exercise regularly, get help to stop smoking, and eat a diabetes-friendly diet.
Regular fingerstick tests or using a continuous glucose monitor can help you and your healthcare team determine if the medications are keeping your glucose levels within a healthy range.
If your blood sugar levels drop below 70 mg/dL (3.9 mmol/l) and you have symptoms like dizziness, blurred vision, sweating, hunger, irritability, and confusion, you might have hypoglycemia. Take a source of fast-acting glucose like table sugar, honey, hard candy, glucose gel, or regular soda (not diet soda).
If you often drive or engage in other activities requiring alertness, take extra care and carry glucose sources, especially in the first few days or weeks after starting sulfonylureas.
Inform your doctor if you get ill, are going through a period of extreme stress, or are starting a vigorous exercise program. You might need to have your dose adjusted.
Because of the risk of photosensitivity, you should use sunscreen and wear protective clothing whenever you’re out in the sun.
What should I remember?
Sulfonylureas are oral medications that help lower blood sugar by stimulating the pancreas to release more insulin and limiting its breakdown in the liver.
They are commonly used alongside metformin in people with type 2 diabetes when extra blood sugar control is needed.
While effective and affordable, sulfonylureas can cause low blood sugar, weight gain, photosensitivity, and allergic reactions. Do not take them with alcohol.
Always talk to your doctor about whether sulfonylureas are right for you and how to use them safely.
