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Side effects are common with almost any medication. What’s less common are side effects that can complicate your recovery from the very condition you’re looking to treat. Case in point: medications that can cause weight gain.
“Often, we think of side effects that cause more [physical] symptoms — dizziness, stomach problems, fatigue,” says John Batsis, M.D., an associate professor in geriatric medicine and nutrition at the University of North Carolina at Chapel Hill. “Weight gain, though, can creep up on you.” And for patients who have other medical issues — osteoarthritis or high blood pressure, for example — “the excess weight can potentially worsen” those conditions, Batsis says.
Yet research suggests a growing number of people take drugs that cause weight gain — most notably, for conditions that are exacerbated by excess weight, including heart disease and type 2 diabetes. Drawing on data from the 2017-2018 National Health and Nutrition Examination Survey (NHANES), a recent study published in Obesity found that 1 in 5 U.S. adults take at least one medication that causes weight gain, the most common being some beta-blockers and diabetes drugs such as insulin and sulfonylureas.

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As side effects go, weight gain may not seem like a big deal, especially if you’re treating a life-threatening condition. But in less serious scenarios, added weight can compromise your overall health. People with obesity are at increased risk for many serious diseases and health conditions, including heart disease, stroke and death, according to the Centers for Disease Control and Prevention (CDC). Even modest weight gain — we’re talking five to 20 pounds — can have negative health effects, one study shows.
Another drawback: Weight gain as a side effect can interfere with medication adherence, says Devika Umashanker, M.D., system medical director with Hartford HealthCare’s Medical and Surgical Weight Loss Program and an obesity medicine specialist.
Keep reading to see why each of these common medications causes weight gain and what you can do to prevent any changes on the scale.
1. Diabetes drugs
Maintaining a healthy weight is an important part of any treatment for type 2 diabetes. But here’s the rub: Some of the drugs prescribed to help manage the condition often result in weight gain. Take, for instance, injectable insulin.
The hormone works by helping the body’s cells absorb glucose. Insulin causes a spike in weight, however, when the cells absorb too much glucose and the body converts it into fat. Not everyone with type 2 diabetes is on insulin. But insulin isn’t the only type 2 treatment that carries this side effect.
Sulfonylureas (such as glyburide, glipizide and glimepiride) reduce blood sugar levels by 20 percent, but they can also cause a weight gain of about 4 to 5 pounds on average, according to a study published in Archives of Medical Science. That’s because they stimulate beta cells in the pancreas to release insulin.