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Drug Info

Does lamotrigine cause weight gain?

This side effect is less likely than on other mood stabilizers
Heidi Borst
By | Mar. 4, 2025 Medically reviewed by Peter Lourgos, MD, JD
Scale next to a pill bottle - Does lamotrigine cause weight gain?

Key takeaways

  • Lamotrigine is primarily used to treat epilepsy and bipolar disorder and is generally considered weight-neutral.

  • Individual responses to lamotrigine can vary, with some patients experiencing weight changes due to lifestyle factors or other medications.

  • Strategies such as maintaining a balanced diet, staying active, and monitoring portion sizes can help manage weight while taking lamotrigine.

  • Alternatives to lamotrigine exist, but many mood stabilizers can also lead to weight gain, so careful consideration is needed when selecting a treatment plan.

In this article:

Lamotrigine (brand name Lamictal) is a prescription anticonvulsant that’s FDA approved to treat epilepsy and maintenance treatment of bipolar I disorder. It may also be prescribed off-label to treat schizophrenia, trigeminal neuralgia, and fibromyalgia. Lamotrigine works by stabilizing mood and preventing seizures, making it a vital part of treatment plans for individuals facing these conditions.

Since many mental health medications affect your waistline, you may be wondering if there’s a risk of weight gain with lamotrigine. The good news is that lamotrigine is weight-neutral, meaning it typically doesn’t cause significant changes in weight. In fact, if you do experience weight changes on lamotrigine, weight loss is more common than weight gain.

Can lamotrigine cause weight gain?

Many mood-stabilizing medications and antiepileptic drugs are known to cause weight gain (including belly fat) by increasing your appetite or causing changes in metabolism. Examples include Lithobid (lithium) valproate, valproic acid, Depakote (divalproex sodium), and Tegretol (carbamazepine).

“Lamotrigine doesn’t typically have any of these side effects, which is why it might be a preferred choice of mood stabilizer drug for some patients, especially those concerned about weight gain,” says Jamie Winn, Pharm.D., a pharmacist based in South Carolina. Dr. Winn explains that lamotrigine reduces mood swings and prevents seizures by calming overactive nerves in the brain, controlling the signals that travel between nerve cells, and preventing them from becoming too erratic.

According to clinical trials, lamotrigine is largely regarded as weight-neutral. One randomized, double-blind study investigated weight changes in patients receiving lamotrigine or divalproex sodium monotherapy. After an 8-week escalation phase and 24-week maintenance phase, the divalproex sodium group experienced significant weight gain, while the lamotrigine group did not.

A similar study compared changes in body weight in patients taking lamotrigine or lithium for 18 months. While patients in the lithium group experienced weight gain, those in the lamotrigine group did not. Additionally, a study of patients receiving lamotrigine for bipolar disorder found no changes in weight or BMI after 12 weeks.

“While lamotrigine is typically weight-neutral or less likely to cause weight gain compared to other anticonvulsants, individual responses can still differ,” says Brian Zachariah, MD, a board-certified psychiatrist with Mindpath Health. He says reasons why you might be gaining weight on lamotrigine include:

  • Your mood isn’t stabilized, potentially causing emotional eating
  • You’re taking other medications, such as antidepressants or antipsychotics, in conjunction with lamotrigine
  • You have comorbidities, such as metabolic conditions, that may influence weight changes during treatment
  • Your lifestyle is sedentary, or you eat an unhealthy diet of high-caloric foods, both of which can lead to weight gain

Common side effects of lamotrigine include:

  • Skin rash
  • Abdominal pain
  • Nausea
  • Diarrhea
  • Drowsiness
  • Dizziness
  • Drowsiness
  • Headache
  • Tremors

If you experience serious side effects, including a severe skin rash (Stevens-Johnson Syndrome), signs of an allergic reaction, or suicidal thoughts, seek medical attention immediately.

Possible drug interactions include:

Does lamotrigine make it hard to lose weight?

Dr. Winn emphasizes that weight gain isn’t commonly seen with lamotrigine. “As with most drugs, it’s worth mentioning that not gaining weight isn’t a guarantee and entirely depends on the patient.”

There is no scientific evidence that taking lamotrigine makes weight loss harder. However, Dr. Winn points out that it could be related to the condition. For example, obesity and metabolic syndrome are common comorbidities of epilepsy, and 68% of individuals seeking treatment for bipolar disorder are overweight or obese.

Tips for managing your weight on lamotrigine

Michael Chichak, MD, instructor with Northeast Ohio Medical University, gives the following tips for managing your weight on lamotrigine:

  • Start with a balanced diet: To help manage weight, limit high-calorie, low-nutrient foods such as sugary snacks and processed foods. Instead, seek to include whole, protein-rich foods along with vegetables, healthy fats, and whole grains, which are nutritious and filling. Keeping your blood sugar levels balanced will also reduce your cravings.
  • Prioritize regular exercise: Make sure to combine cardiovascular activities alongside resistance training in your schedule. While cardio helps burn calories, resistance training is key to maintaining muscle, which enables a proper metabolism. These are two extremely important factors when dealing with weight changes caused by medication.
  • Reduce stress levels: Stress activates cortisol, a hormone that can lead to unwanted weight gain. Yoga, exercise, or even meditation can help lessen stress and allow you to remain healthy overall.
  • Maintain consistent sleep patterns: Try to get seven to nine hours of sleep each night. Sufficient sleep balances out hormones such as leptin and ghrelin, which help regulate hunger and determine when to stop eating to minimize overindulging in food.
  • Consult a healthcare professional: Speak to your prescribing healthcare provider for medical advice about any issues related to your weight. They could alter your dosage or change it to something that would not have as much negative impact on your body, making weight management safer and more efficient.

Alternatives to lamotrigine

Lamotrigine is frequently noted for its tolerability among patients. However, If you’re worried about weight gain associated with lamotrigine, several alternatives exist. While many mood stabilizers, such as lithium and valproate, are known to cause weight gain, Dr. Zachariah says that weight-neutral alternatives include carbamazepine or oxcarbazepine. He says another alternative, Topamax (topiramate), is associated with weight loss in most individuals.

Even though lamotrigine is not typically associated with weight gain, individual experiences can vary based on factors like concurrent medications, health conditions, and lifestyle factors. It’s essential to consult your healthcare providers to customize a treatment option that considers weight management in conjunction with mental health.