Low blood sugar on GLP-1 medicines

In short

Hypoglycemia means blood sugar below about 70 mg/dL. It matters most for people with type 2 diabetes who also take insulin or sulfonylureas.

Why it happens

GLP-1 medicines boost insulin mostly when blood sugar is high, which is why low blood sugar is uncommon when they are used alone.

Insulin and sulfonylureas, such as glipizide or glyburide, push blood sugar down whether it is high or not. Labels note that the dose of these medicines may need to be lowered when a GLP-1 is added. Eating much less on a GLP-1 adds to the risk.

When it starts and fades

Risk is highest when a GLP-1 is first added to insulin or a sulfonylurea, and after dose increases, when appetite drops most.

People without diabetes who are not on these medicines are unlikely to have true hypoglycemia from a GLP-1 alone.

What helps

• Know the signs: shakiness, sweating, fast heartbeat, hunger, irritability, confusion or blurry vision.
• If you have a meter, check your blood sugar when symptoms appear.
• Keep fast sugar on hand, like glucose tablets or 4 ounces of juice.
• Use the 15-15 rule for mild lows: about 15 grams of fast sugar, then recheck in 15 minutes.
• Tell your prescriber about every diabetes medicine you take before starting a GLP-1.
• Do not skip meals for long stretches if you take insulin or a sulfonylurea.