8 Common Medications That Can Cause Weight Gain—and How to Manage It

3. Beta-blockers

Beta-blockers work by slowing the heart rate, the heart’s workload and its output of blood, all of which lowers blood pressure. That’s why they’re often prescribed to treat hypertension, angina and irregular heartbeat. If you’re on a beta-blocker, no one has to tell you the side effects include fatigue, insomnia and a slow heartbeat. All of those can add up to a less physically active lifestyle, which — no surprise — may result in extra weight.

“Weight gain often occurs in the first few months after initiating beta-blockers like atenolol or metoprolol,” Batsis says. That’s “thought to be due to changes in metabolism, insulin sensitivity and impact on skeletal muscle metabolism.”

What to do: If you’re on a beta-blocker and weight gain is an issue, talk to your doctor about possible alternatives, such as carvedilol (Coreg), a nonspecific beta-blocker; angiotensin converting enzyme (ACE) inhibitors; angiotensin receptor blockers (ARBs); or calcium blockers, Batsis says.

Beta-blockers that may cause weight gain include:

• Acebutolol (Sectral)
• Atenolol (Tenormin)
• Bisoprolol (Zebeta)
• Metoprolol (Lopressor, Toprol XL)
• Nadolol (Corgard)
• Nebivolol (Bystolic)
• Propranolol (Inderal LA, InnoPran XL)

4. Oral corticosteroids

Oral corticosteroids are prescribed for everything from severe allergies and rashes to rheumatoid arthritis, but they come with side effects — among them, weight gain. The culprit? Fluid retention.

“Electrolyte imbalances lead to water retention,” explains Dr. Devika Umashanker, medical director for obesity medicine at the Hartford HealthCare Comprehensive Weight Management Program.

“Oral steroids also reduce the body’s sensitivity to insulin, leading to insulin resistance,” she says. That, in turn, ramps up production of the hunger hormone ghrelin, which stimulates appetite.

What to do: To avoid weight gain, Umashanker recommends a diet rich in low-glycemic foods such as fruits and vegetables, beans, minimally processed grains, low-fat dairy and nuts, all of which are “slowly digested and absorbed, causing a slower and smaller rise in blood sugar levels.” 

Avoid unnecessary use of corticosteroids, which are commonly prescribed at urgent care centers for allergies and upper respiratory infections.

5. Migraine meds

Talk about a vicious cycle: If you’re overweight and suffer from migraines, extra weight puts you at greater risk for more frequent and more severe migraines. 

Migraine medications that may cause weight gain include:

• Propranolol (Inderal)
• Divalproex sodium (Depakote)

According to the American Migraine Foundation, people at a healthy weight who experience migraines have about a 3 percent chance of developing chronic headaches. For people who are overweight and for people with obesity, the chance of chronic migraine is three to five times greater. 

What to do: If you’re on a migraine-preventive medication that’s causing weight gain, talk to your doctor about switching to one that has the potential to suppress appetite, such as topiramate (Topamax), zonisamide (Zonegran), protriptyline (Vivactil), along with phentermine plus topiramate (Qsymia).

6. Antihistamines

It’s easy to assume that over-the-counter meds don’t carry serious side effects because they’re so readily available. But just because something is available without a prescription doesn’t mean it’s risk-free. Research suggests that taking an antihistamine on a regular basis — to treat allergies, for instance — can result in weight gain. 

Antihistamines that may cause weight gain include:

• Cyproheptadine (Periactin)
• Cetirizine (Zyrtec)
• Fexofenadine (Allegra)
• Desloratadine (Clarinex)

“The major study, which demonstrates the relationship between antihistamines and weight gain, comes from the journal Obesity,” Umashanker says. “It revealed that men who used antihistamines had an average weight of 214 pounds versus 192 for those not on antihistamines, and women had an average weight of 176 pounds on antihistamines versus 166 pounds for those not on antihistamines.”

Why? Histamine, a chemical in the body known to be a key player in allergic responses, decreases hunger by affecting the appetite control center in the brain, so it makes sense that an antihistamine would have the opposite effect, interfering with the “I’m full” signal coming from the rest of the body, according to the Obesity Medicine Association. 

What to do: Talk to your doctor about which antihistamine may be best for you. Generally, if your allergies are sinus related, you can try nasal saline or a steroid nasal spray, as they don’t have systemic side effects. 

7. Anti-epilepsy drugs

​​A review of research published in Epilepsia suggests that people with epilepsy (a brain disorder that causes seizures) exercised less and tended to have obesity even if their seizures were under control. Conventional wisdom suggests that a fear of doing anything that could provoke a seizure would figure into why people with epilepsy are less inclined to be physically active. But anti-epilepsy drugs have been shown to play a significant role in weight gain:

• Valproic acid (Depakene)
• Gabapentin (Neurontin)
• Pregabalin (Lyrica)
• Possibly carbamazepine (Carbatrol)

What to do: If you’re taking any of these and experiencing weight gain, talk to your doctor about possible alternatives such as topiramate (Topamax) or zonisamide (Zonegran), both of which are also prescribed for migraines and associated with weight loss.

8. Antipsychotics

People with mental health disorders are two to three times more likely to have obesity (meaning a body mass index (BMI) of 30 or more) than the general population. A review of research examining antipsychotic medicine explains why: Most of those drugs cause weight gain. Over the course of treatment, around 7 in 10 patients will gain weight — rapidly in the initial period after starting these meds, but it continues over the long term. The risk appears to be highest with:

• Olanzapine (Zyprexa)
• Clozapine (Clozaril)

Making matters worse, these types of drugs impair glucose function and increase cholesterol and triglycerides, putting patients more at risk for developing metabolic syndrome, according to a review of research in Neuropsychiatric Disease and Treatment.

What to do: If you’re taking an antipsychotic for bipolar disorder, schizophrenia or depression and you’re experiencing weight gain, talk to your doctor about newer medications on the market. “They tend to have lower risk of weight gain,” Batsis says. Keep in mind that everybody is different, he hastens to add. “While we can generalize, these medications may affect different individuals in different ways.”

Why do some medications cause weight gain?

​​The source of what causes weight gain varies among medications. Some may increase your appetite, tempting you to eat more, resulting in a few pounds creeping on. Others might slow your metabolism down so calories aren’t burned as quickly. Certain classes of drugs may make your body retain water. Although this wouldn’t mean you’ve put on fat, it will make you weigh more when you hit the scale. In other instances, the way your body stores and absorbs sugar and other nutrients may be affected.

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 National Health and Nutrition Examination Survey, a 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.

Another drawback: Weight gain as a side effect can make people less likely to stick to their prescribed medication, Umashanker says.

Always consult your doctor before making any changes to your medication, including stopping or switching.

What to do if medications cause weight gain

If switching meds isn’t an option, that doesn’t mean you’re powerless over the extra pounds. Consider meeting with a registered dietitian who can help you learn how to make healthier food choices.

Getting more exercise can also help treat weight gain, especially a combination of cardio (such as brisk walking) and strength training. “Countering medication-induced weight loss is difficult,” Batsis says. “Trying to engage individuals in health promotion efforts is key.” 

Although it may be tempting to turn to an anti-obesity drug to lose the unwanted pounds, Batsis recommends against doing so. “Treating side effects of one medication with another can be problematic and lead to what we term polypharmacy,” he says. “That, in and of itself, can lead to adverse events.”