8 Serious Side Effects of Blood Sugar Medications

Many medications can help people with diabetes manage their blood sugar. While serious side effects are usually rare and vary by drug type, knowing about them can help you recognize what to look for and when to seek medical care.

1. Hypoglycemia

Hypoglycemia occurs when your blood glucose, or blood sugar, level is low, which is below 70 milligrams (mg)/deciliter (dL).

Moderate hypoglycemia occurs when your blood sugar level falls between 54-68 mg/dL. Severe hypoglycemia, which occurs when blood sugar falls below 54 mg/dL, is a dangerous medical emergency that requires prompt treatment.

Insulin and a type of drug called sulfonylureas (which includes glimepiride, glyburide, and glipizide) are more likely to cause low blood sugar. The risk of severe hypoglycemia increases when you take any kind of diabetes medication with insulin or a sulfonylurea.

Regardless of which diabetes drug you use, your healthcare provider will instruct you on how often to monitor your blood sugar and give you an action plan for when your blood sugar is too high or too low.

2. Stomach Issues

Common side effects of glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP)/GLP-1 agonist drugs, such as Ozempic (semaglutide) and Mounjaro (tirzepatide), include gastrointestinal (GI) problems such as:

• Nausea or vomiting
• Diarrhea
• Upset stomach
• Constipation

These side effects are often temporary and typically subside as your body adjusts to the medication. However, severe or prolonged nausea, vomiting, or diarrhea could lead to dehydration and kidney problems.

It is important to drink enough fluids, especially if you are having stomach-related side effects. Report GI issues to your healthcare provider if they are severe or do not go away.

3. Lactic Acidosis

Lactic acidosis is a rare but serious condition that happens when lactic acid builds up in the body. Lactic acidosis can cause symptoms like:

• Nausea or vomiting
• Weakness
• Muscle cramps
• Trouble breathing

Metformin has a boxed warning—the most serious type of warning required by the Food and Drug Administration (FDA)—for lactic acidosis. The risk is higher in people who drink alcohol, have kidney or liver problems, or take certain other medicines. If you take metformin, your healthcare provider will monitor you closely.

4. Pancreatitis

Pancreatitis, or inflammation of the pancreas, is a rare but serious side effect sometimes associated with GLP-1 and GIP/GLP-1 agonist drugs.

People who take a dipeptidyl peptidase-4 (DPP-4) inhibitor may also be at higher risk for pancreatitis. Examples of DPP-4 inhibitors include:

• Tradjenta (linagliptin)
• Januvia (sitagliptin)
• Saxagliptin
• Nesina (alogliptin)
• Any combination drug that contains one of these ingredients

Tell your healthcare provider if you have a history of pancreatitis, as they will typically avoid prescribing these types of drugs to people with this history. Call your healthcare provider right away if you are taking a diabetes medication and have severe stomach pain, which may spread to the back, with or without vomiting.

5. Diabetic Ketoacidosis

Diabetic ketoacidosis (DKA) can occur in people with diabetes when there is a build-up of acids in the blood.

It is more common in people with type 1 diabetes than those with type 2, and others who may be at higher risk include people who drink alcohol, eat a diet very low in carbohydrates, or have other medical conditions.

Although rare, it is a serious side effect that can occur with a group of diabetes drugs called sodium-glucose transport 2 (SGLT2) inhibitors. These drugs include:

• Jardiance (empagliflozin)
• Invokana (canagliflozin)
• Farxiga (dapagliflozin)
• Steglatro (ertugliflozin)
• Combination drugs that contain any of the above ingredients

If you are taking an SGLT2 inhibitor, seek medical attention immediately if you experience symptoms of DKA, even if your blood sugar level is not high. Symptoms can include:

• Nausea or vomiting
• Stomach pain
• Trouble breathing
• Feeling unusually tired

6. Allergic Reactions

Allergic reactions are a rare but serious side effect that can occur with any drug, including any type of diabetes drug. Allergic reactions can range from mild to severe.

Seek medical attention immediately if you experience symptoms of an allergic reaction, such as hives, difficulty breathing, or swelling of the face, lips, tongue, or throat.

7. Severe Joint Pain

DPP-4 inhibitors may cause severe and disabling joint pain in rare cases. If you are taking a drug from this class, be alert to any symptoms of severe joint pain. Call your healthcare provider if you are taking a DPP-4 inhibitor and have joint pain that is severe or does not go away.

8. Fournier’s Gangrene

Fournier’s Gangrene is a rare but serious infection associated with SGLT2 inhibitors. The FDA requires a boxed warning for this serious side effect.

If you are taking an SGLT2 inhibitor, seek medical attention immediately if you develop a fever above 100.4 F, feel unwell, or experience redness, tenderness, or swelling in the genital or rectal area.