Anticonvulsants for Weight Loss

Reviewed by: HU Medical Review Board | Last reviewed: August 2023

Anticonvulsant drugs are mainly used to treat seizures and certain neurological disorders. These drugs are also known as anti-seizure medicines. But some of them have been studied for their potential role in weight loss and the treatment of obesity.1-4

How anticonvulsants affect weight is not fully understood. Anticonvulsants are approved by the US Food and Drug Administration (FDA) to treat seizures. But using anticonvulsants for weight loss is not yet FDA approved and is considered an “off-label” use. Off-label use means taking a drug for something it is not approved to treat. More research and larger studies about anticonvulsants are necessary.1,3

How do anticonvulsants work?

Anticonvulsants work by changing the electrical activity and chemical signaling in the brain. Anticonvulsants can enhance inhibitory chemicals like gamma-aminobutyric acid (GABA) to calm overexcited neurons. They can also suppress the effects of excitatory chemicals, such as glutamate, that can trigger seizures.1

Anticonvulsants stabilize brain activity and help prevent abnormal electrical discharges. These drugs play a major role in managing seizures. They are used to treat various neurological conditions.1

Examples of anticonvulsants for weight loss

There are currently 2 anticonvulsants that have been studied for weight loss: topiramate (Topamax®) and zonisamide (Zonegran®).2-4

Topiramate (Topamax®)

Topiramate is an anticonvulsant that has shown some potential for weight loss in clinical trials. The exact way it works for weight loss is not known, but experts think it reduces appetite and increase feelings of fullness (satiety) by affecting certain brain chemicals.1,2,4

By enhancing feelings of fullness and reducing food intake, topiramate may lead to weight loss. It is often used off label for weight management in people with obesity. Topiramate can have significant side effects, and its use for weight loss should be carefully monitored by a healthcare professional.2

Topiramate is sometimes combined with phentermine, an anorectic drug that is often used in weight loss treatments.2

For more information, read the full prescribing information of topiramate.

Zonisamide (Zonegran®)

Zonisamide is another anticonvulsant that has been studied for its potential as a weight-loss drug. Similar to topiramate, the way zonisamide works for weight loss still is not fully understood. It is believed to affect chemicals and processes in the brain that are involved in appetite regulation.1,3

Clinical trials have shown that zonisamide may help reduce body weight and improve metabolism in people with obesity. As with topiramate, the use of zonisamide for weight loss is considered off label. Its potential benefits and risks should be evaluated by a healthcare professional.3

For more information, read the full prescribing information of zonisamide.

What are the possible side effects?

Side effects can vary depending on the specific drug you are taking.

The most common side effects of topiramate are:2,5

  • Abnormal vision and vision changes
  • Pins and needles sensation in the skin (paresthesia)
  • Anorexia
  • Weight loss
  • Fatigue
  • Dizziness
  • Fever

The most common side effects of zonisamide are:3,6

  • Serious skin rashes
  • Drowsiness
  • Anorexia
  • Dizziness
  • Problems with balance and coordination (ataxia)
  • Agitation or irritability
  • Trouble with memory and/or concentration

These are not all the possible side effects of anticonvulsant drugs. Talk to your healthcare provider about what to expect when taking anticonvulsants. You also should call your healthcare provider if you have any changes that concern you when taking anticonvulsants.

Other things to know

Do not take these drugs if you are pregnant, intending to become pregnant, or breastfeeding. Anticonvulsants could cause harm to an unborn child.2,5,6

While these drugs may show promise for weight loss, they are not a stand-alone solution for treating obesity. They should be part of a comprehensive weight management plan that includes a balanced diet, regular exercise, and lifestyle changes.2,3

If you are curious about anticonvulsants for weight management, talk with your healthcare provider. They can provide advice and guidance based on your specific situation.

Before beginning treatment for obesity, tell your healthcare provider about all your health conditions and any other drugs, vitamins, or supplements you take. This includes over-the-counter drugs.

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