Diabetes Health Center
Hypoglycemia and Diabetes
Causes of Hypoglycemia in Diabetes
In people with diabetes, hypoglycemia (low blood sugar) develops when there is not enough glucose in your body. A number of different factors can cause hypoglycemia, including certain medications and diet. Certain medical conditions can also make hypoglycemia more common in people with diabetes.
Hypoglycemia Symptoms
Most people feel symptoms of hypoglycemia when their blood glucose is 70 mg/dL or lower.
Each person with diabetes may have different symptoms of hypoglycemia. You will learn to recognize your symptoms.
Early symptoms of hypoglycemia may include:
- Confusion
- Dizziness
- Feeling shaky
- Hunger
- Headaches
- Irritability
- Pounding heart; racing pulse
- Pale skin
- Sweating
- Trembling
- Weakness
- Anxiety
Without treatment, more severe hypoglycemia symptoms may develop, including:
- Headache
- Feeling irritable
- Poor coordination
- Poor concentration
- Numbness in mouth and tongue
- Passing out
- Nightmares or bad dreams
- Coma
Diabetes Medications Linked to Hypoglycemia
Certain types of oral diabetes medicines can cause low blood sugars. These include the sulfonylureas and meglitinides. Alpha-glucosidase inhibitors, biguanides, and thiazolidinediones alone should not cause hypoglycemia but can when used with other diabetes medicines.
The older oral diabetic medications tend to cause low sugars more frequently than newer drugs used to treat type 2 diabetes. Examples of these first generation drugs include:
- Orinase (tolbutamide)
- Tolinase (tolazamide)
- Diabinese (chlorpropamide)
Other drugs that can cause low blood sugars include the use of alcohol, aspirin, Coumadin (warfarin), Zyloprim (allopurinol), Benemid or Probalan (probenecid) with diabetic medications.
Hypoglycemia can also occur if you take too much insulin for the amount of carbohydrates consumed.
Ask your health care provider if your medication can cause hypoglycemia.
Diet and Hypoglycemia
Hypoglycemia can occur following a meal that contains a lot of simple sugars. This condition is called reactive hypoglycemia. It may also develop if a person with diabetes misses a snack, doesn't eat the whole meal, eats later than usual, doesn't eat when ill, or drinks alcohol without eating any food. Therefore, it's particularly important for people with diabetes to not skip meals, particularly when they're taking diabetes medications.
Intense exercise may also trigger a hypoglycemic reaction.
Hypoglycemia Treatment
If you suspect you have low blood sugar, check your blood glucose level.
If you have blood glucose levels that frequently drop after meals that have a high content of simple sugars, a way to diminish these episodes of reactive hypoglycemia is through a more balance diet. Avoid simple sugars and eat frequent small meals during the day.
If you experience low blood glucose when you haven't eaten (fasting hypoglycemia) have a snack before bedtime, such as a protein or a more complex carbohydrate.
Your doctor may determine that you are taking too much insulin that peaks toward the evening to morning hours. In that case, he or she may decrease your insulin dose or change the time when your last dose of insulin is given.
WebMD Medical Reference provided in collaboration with the Cleveland Clinic![]()



