Medications That May Contribute to Weight Gain

Several medications can work against weight loss, slowing the rate of weight loss or contributing to a plateau.
Medications That May Contribute to Weight Gain
Medications That Alter Brain Chemistry
Medications used to treat schizophrenia, bipolar disorders, depression, epilepsy and migraines often have the side effect of weight gain. This side effect is thought to be due to the drugs affect on neurotransmitters, such as serotonin and norepinephine, which are found in the brain and are integral to many mental processes, including mood regulation, hunger and satiety.

Weight gain is particularly linked to many of the newer drugs used to treat psychiatric disorders. In an analysis of dozens of smaller drug studies, clozapine and olanzapine showed the greatest risk of weight gain and ziprasidone had the least risk.2 Lithium, a medication used to stabilize mood, may also work against weight loss.

Successful treatment of depression is also linked with weight gain or hindered weight loss. The reason for this finding may be either a reversal of the lack of appetite that is commonly seen with depression or a side effect of the medication used to treat the problem. Tricyclic antidepressants, especially amitriptyline, and monoamine oxidase inhibitors, such as phenelzine and tranyclypromine are more likely to cause a weight gain than selective serotonin reuptake inhibitors (SSRIs). As a group of related drugs, the SSRIs have different impacts on weight, depending on which drug is used.3 For example, paroxetine is linked with weight gain, nefazadone is weight neutral, and bupropion often promotes a modest weight loss.4

Many medications used for the treatment of epilepsy and migraine headaches are linked with weight gain. An exception is topiramate, an antiseizure drug that is associated with weight loss.

Medications For Diabetes, Hypertension, Cancer and Inflammatory Disorders
Drugs used in the treatment of diabetes, including insulin, thiazolidinediones, and sulfonylureas, may hinder weight loss. One diabetes medication, biguanide metformin, may promote weight loss.5

The beta-adrenergic blockers, including propranolol, that are used to treat high blood pressure, are associated with a modest weight gain during the first few months of treatment.6 Likewise, the medications used treat breast cancer may cause a small weight gain in some women.7

Corticosteroids, used primarily to reduce inflammation, are also linked with weight gain—with the higher the dose used, the greater the likelihood and degree of weight added. Nonsteroidal anti-inflammatory drugs (NSAIDs) do not appear to affect weight.

While there are several drugs that affect weight and have the potential to hinder weight loss, it is important to understand that not all of the medications used to treat these conditions affect body weight nor does every drug have the same effect on every person who takes it. In many cases, it is possible for a physician to prescribe medications that treat the medical problem without an adverse affect on weight.

Generic and Brand Names of Medications that Affect Weight

Used in the Treatment of: Generic Name Brand Names
Psychiatric Disorders
  • Olanzapine
  • Clozapine
  • Lithium
  • Ziprasidone
Eskalith, Lithobid
  • Amitriptyline
  • Paroxetine
  • Phenelzine
  • Tranylcypromine
  • Nefazadone
  • Bupropion
Wellbutrin SR
  • Valproate
  • Gabapentin
  • Carbamazepine
  • Topiramate
Inflammatory Disorders
  • Corticosteroids
  • Insulin
  • Sulfonylureas
  • Thiazolidinediones
  • Biguanide metformin
Glucotrol, Diabeta
Avandia, Actos
  • Propranolol

This content is reviewed regularly. Last updated November 6, 2011.

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1 Kulkarni SK, Kaur G. Pharmacodynamics of drug-induced weight gain. Drugs Today. 2001 Aug;37(8):559-572.

2 Allison DB, Mentore JL, Heo M, et al. Antipsychotic-induced weight gain: a comprehensive research synthesis. Am J Psychiatry 1999 Nov;156:1686-1696.

3 Fava M. Weight gain and antidepressants. J Clin Psychiatry. 2006:61 Suppl 11:37-41.

4 Croft H, Houser TL, Jamerson BD, et al. Effect on body weight of bupropion sustained-release in patients with major depression treated for 52 weeks. Clin Ther. 2002 Apr;24(4):662-72.

5 Purnell JQ, Weyer C. Weight effect of current and experimental drugs for diabetes mellitus: from promotion to alleviation of obesity. Treat Endocrinol. 2003;2(1):33-47.

6 Sharma AM, Pischon T, Hardt S, Kunz I, Luft FC. Hypothesis: Beta-adrenergic receptor blockers and weight gain: A systematic analysis. Hypertension. 2001 Feb;37(2):250-4.

7 Ingram C, Brown JK. Patterns of weight and body composition change in premenopausal women with early stage breast cancer: has weight gain been overestimated? Cancer Nurs. 2004 Nov-Dec;27(6):483-90.