Is Your Medicine Cabinet Making You Fat?
Experts explain how certain prescription drugs can cause unwanted weight gain
By Charlene Laino
Reviewed By Louise Chang, MD
You've been watching your diet and following your usual exercise routine. But your pants seem a little tight and, sure enough, the scale shows that you've gained five pounds in the past month.
What's going on?
This may be hard to swallow, but a medication your doctor prescribed could be to blame. Certain prescription drugs used to treat mood disorders, seizures, migraines, diabetes, and even high blood pressure can cause weight gain - sometimes 10 pounds a month. Some steroids, hormone replacement therapy, and oral contraceptives can also cause unwanted pounds to creep up on you.
But even if you suspect a prescription medication is causing weight gain, never stop taking the drug without consulting your doctor, experts stress.
"Stopping some of these medications on your own can have very serious consequences," says Louis Aronne, MD, director of the Comprehensive Weight Control Program in New York City and president of the North American Association for the Study of Obesity. "It has to be done very carefully."
Madelyn H. Fernstrom, PhD, director of the Weight Management Center at the University of Pittsburgh Medical Center, agrees. Even if a medication causes weight gain, "an extra 10 pounds may be worth the trade-off of what that medication is doing for your overall health," she says.
Common Offenders That Can Cause Weight Gain
While no one knows exactly how many prescription drugs can cause weight gain, experts estimate the list includes more than 50 common medications.
Steroids such as prednisone, older antidepressants such as Elavil and Tofranil, and second-generation antipsychotics like Zyprexa are the biggest -- and most recognized -- promoters of weight gain, Fernstrom says.
Some other common offenders, says Fernstrom, include the antidepressants Paxil and Zoloft, the antiseizure medication Depakote, diabetes drugs like Diabeta and Diabinese, and the high blood pressure drugs Cardura and Inderal. Heartburn drugs like Nexium and Prevacid may also cause drug-induced weight gain.
Fernstrom tells WebMD that the medication-associated weight gain can be modest -- or as much as 30 pounds over several months.
"And in some cases, it is unrelated to the action of the drug itself," she adds. "For example, if an antidepressant makes people feel better, their appetite may be restored and they eat more."
Making matters more complicated is that some drugs, like Prevacid and Nexium, can cause weight gain in some people and weight loss in others.
"Not all drugs have the same side effects for all people," she says. "You have to work with your doctor to find the drug that's right for you."
Aronne says he warns against putting too much stock in a list of specific drugs that cause weight gain.
"What you need to know," he tells WebMD, "is that certain types of drugs can cause weight gain." But in almost every case, the doctor will be able to switch you to another medication that has the same desirable effects but which will not cause weight gain and may even help you to shed a few pounds, he says.
For example, while some drugs used to treat depression and other mood disorders can cause weight gain, the antidepressants Wellbutrin and Prozac tend to help people lose weight, says Aronne, who is also clinical professor of medicine at Weill-Cornell Medical College in New York City.
Ditto for diabetes medications. "Yes, some can induce weight gain, but Glucophage and Precose are both weight-neutral, while two newer drugs -- Byetta and Symlin -- can actually help you lose weight," he says.
As for medications used to treat seizure disorders and headaches, Aronne says that Zonegran and Topamax are good alternatives that are both associated with weight loss.
Aronne recalls the case of one 190-pound woman being treated for migraine headaches who came to his obesity clinic. His team tried a variety of measures, even a liquid diet, to help her shed the unhealthy excess weight, but she stabilized after losing only 10 pounds.
"Then we switched her to a different medication, Topamax, for her migraines," he recalls. "She lost 50 pounds and has stabilized at a healthy 133 pounds. I can offer dozens of more examples just like this."