13 Drugs That Can Make You Gain Weight
Pharmaceuticals and fat
About 70% of people in the United States are overweight and, in a cruel catch-22, many of the drugs used to treat obesity-linked conditions such as diabetes, high blood pressure, and depression can themselves cause weight gain.
"Patients and doctors need to be more aware of this—it's an under-recognized driver of our obesity problem," says Lawrence Cheskin, MD, director of the Johns Hopkins Weight Management Center, in Baltimore.
Here are 13 drugs that could cause you to gain weight. But don't stop taking your (possibly life-saving) medicine! There are strategies for keeping off the pounds.
Paxil is one of the best anxiety treatments, but if you gain weight while using it you could talk with a doctor about switching to a more weight-neutral SSRI such as Prozac or Zoloft, says Louis Aronne, MD, director of the Comprehensive Weight Control Program at New York-Presbyterian/Weill Cornell Medical Center, in New York City. (Dr. Aronne is a consultant for the maker of Paxil.)
Depakote (valproic acid)
A 2007 study of epilepsy patients found that 44% of women and 24% of men gained 11 pounds or more while taking Depakote for about a year. The drug affects proteins involved in appetite and metabolism, although it's not clear why it appears to affect women more than men.
Lithium, another mood stabilizer for treating bipolar disorder, is also associated with weight gain, albeit less than Depakote.
A 60-week study found that, although patients on Prozac shed more than the placebo group (up to 11 pounds in the first six months), they started to regain the weight about halfway through the study.
Dr. Cheskin says the reason could be that patients develop tolerance to the satiety effect. "If someone is trying to lose weight, and is on an SSRI for depression, I will often switch to Wellbutrin (bupropion)," which is associated with weight loss, he says.
This side effect can be a good thing, however. Remeron is sometimes given to elderly people who are underweight to improve their appetite, Roerig says.
These drugs, used for schizophrenia and bipolar disorder, have potent antihistamine activity and inhibit serotonin, which may trigger weight gain.
The diabetes drug metformin may help keep weight off, as can switching to weight-neutral antipsychotics like Geodon (ziprasidone) and Abilify (aripiprazole).
A 2006 survey of long-term oral-corticosteroid users suggested 60% to 80% had gained weight. Higher doses, such as those for asthma and inflammatory bowel disease, are more likely to have this effect than lower doses, such as those for rheumatoid arthritis.
It can be hard to counteract the side effects of long-term steroid use, but exercise, diet, and, in some cases, taking metformin can help, Dr. Aronne says.
Thorazine, along with Mellaril (thioridazine), has antihistamine activity, which increases your appetite and is sedating, says James Roerig, associate professor of clinical neuroscience at the University of North Dakota School of Medicine and Health Sciences, in Fargo.
These drugs may cause less weight gain than Zyprexa and Clozaril. Still, they aren't as effective at treating schizophrenia, and may have other side effects, such as motor problems, says Roerig. (Roerig gets research funding from Eli Lilly, the maker of Zyprexa.)
Elavil, Endep, Vanatrip (amitriptyline)
TCAs affect neurotransmitters involved in energy and appetite, such as serotonin, dopamine, and acetylcholine, but their antihistamine activity is probably the reason for weight changes, Roerig says.
These drugs are given less often for depression because an overdose can damage the heart. Lower doses can prevent migraines, but a 2006 study found that 30% of people taking amitriptyline for migraines gained more than 5% of their body weight in 26 weeks.
Allegra (fexofenadine and pseudoephedrine)
Antihistamine activity, however, is crucial for the effectiveness of allergy drugs. A 2010 study found that people taking prescription antihistamines such as Allegra and Zyrtec were 55% more likely to be overweight than those not taking the drugs.
Blocking histamine can disrupt an enzyme in the brain that helps regulate food consumption.
Diabinese, Insulase (chlorpropamide)
Sulfonylurea drugs such as Diabinese and Insulaseand others such as Actos and Prandinstimulate insulin production or activity, which lowers blood sugar and may increase appetite.
Metformin, Byetta, and Januvia are more likely to cause weight loss, Dr. Aronne says. (Dr. Aronne receives research support from and consults for the companies that make Byetta and other drugs.)
One study found that people gained nearly 11 pounds on average during their first three years taking insulin. About half of the weight gain is thought to occur in the first three months.
Dr. Cheskin calls the weight-promoting effect of insulin paradoxical. "The things that we use to treat some conditions that are the result of obesity, like [type 2] diabetes, are prone to make you more obese," he says.
One study found that people taking Tenormin gained about 5 more pounds than the placebo group, and research suggests that most of the weight is gained in the first few months. These drugs can slow calorie burning and cause fatigue.
Newer beta-blockers, calcium channel blockers, and ACE inhibitors are less likely to cause weight gain, Dr. Cheskin says.
In fact, only the long-acting, progestin-only injectable called depot medroxyprogesterone acetate (DMPA) has been consistently linked with weight gain.
Research suggests that young women who were obese to begin with are most prone to weight gain on DMPA.