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Lamotrigine is a commonly-prescribed medication that’s been on the market in the United States for more than 25 years. Like almost all drugs, lamotrigine can cause side effects and other potential risks.

In 2021, the Food and Drug Administration (FDA) issued a new warning about a possible link between the use of lamotrigine and the risk of arrhythmias in people with heart disease. The agency also said it would update the public with additional information from studies.

The announcement left many people concerned about the safety of the medication. For example, they questioned whether people with heart problems can take lamotrigine or if it can cause high cholesterol. Scientists are exploring those questions by reviewing existing data and conducting new research.

In this article, we’ll discuss the potential side effects of lamotrigine, what healthcare professionals use it for, and why you might want to consult your healthcare team before starting this medication.

Lamotrigine is a prescription medication that healthcare professionals can use to treat seizures in adults and children with epilepsy or a condition called Lennox-Gastaut syndrome. They can also prescribe it to adults with bipolar disorder to help stabilize mood changes.

The medication is in a class of drugs called anticonvulsants. It works by lessening irregular electrical activity in the brain.

Lamotrigine is sold under the brand name Lamictal and comes in different formulations, including:

  • quick-swallow tablets
  • extended-release tablets
  • orally-disintegrating tablets
  • chewable, dispersible tablets

According to the FDA, a review of studies suggested that lamotrigine can increase the risk of serious arrhythmias in people with heart conditions, such as:

The agency noted that the risk of arrhythmias may increase even more if people with heart conditions take lamotrigine combined with a sodium channel blocker.

Though this report didn’t address the correlation between lamotrigine and cholesterol, other studies looked at the relationship, and several found no negative association.

A 2018 study examined the effect of commonly-prescribed antiseizure drugs, including lamotrigine, levetiracetam, carbamazepine, phenytoin, on cholesterol levels. Results showed lamotrigine did not produce a significant increase in total cholesterol, high-density lipoprotein, low-density lipoprotein, or triglycerides.

However, carbamazepine, phenytoin, and levetiracetam did significantly increase total cholesterol levels. The authors concluded that lamotrigine doesn’t seem to have a substantial effect on lipid profiles and may be a better treatment choice for some individuals.

In another 2018 study, researchers analyzed how the drugs lamotrigine, carbamazepine, and levetiracetam affected older adults taking cholesterol-lowering medications. They found cholesterol levels were significantly lower in people taking lamotrigine compared with those taking carbamazepine and levetiracetam.

A small, older study from 2009 found that participants who changed from taking carbamazepine or phenytoin to lamotrigine saw a decrease in total cholesterol levels just 6 weeks after making the switch.

Aside from potential heart issues, there are other side effects and risks associated with the use of lamotrigine.

The FDA issued the following warnings about the medication:

  • In 2006, the agency released an alert to inform the public that taking lamotrigine during pregnancy may increase the risk of oral clefts in newborns.
  • In 2009, the agency provided information showing that lamotrigine might increase the risk for suicidal thoughts and behaviors.
  • In 2010, the FDA informed the public that lamotrigine might cause a condition called aseptic meningitis.
  • In 2018, the FDA shared a safety announcement to warn that lamotrigine might trigger a rare but serious reaction that overly activates the body’s immune system.

FDA warning about lamotrigine

Lamotrigine contains a black box warning from the FDA to alert consumers about the risk of life threatening rashes, including Stevens-Johnson syndrome and toxic epidermal necrolysis.

This risk can often be higher in children than in adults, and may be more likely in individuals who take higher doses of lamotrigine or also take the medication valproate.

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Some other possible side effects of lamotrigine include:

  • nausea or vomiting
  • back, chest, or abdominal pain
  • swelling
  • dry mouth
  • missed periods or pain during menstruation
  • changes in weight
  • constipation
  • general achiness or weakness
  • insomnia
  • drowsiness
  • dizziness or difficulty with balance
  • vision problems
  • headache
  • anxiety or irritability

Studies have shown that older anticonvulsants, such as carbamazepine, phenytoin, and valproate, may affect bone mineral density and increase the risk of bone fractures. However, data on lamotrigine are limited. For example, one 2017 study involving rats showed that the medications didn’t affect bone strength, bone mineral density, or bone turnover.

When to talk with your healthcare team

If you have a heart condition or are worried about potential heart complications, consult your doctor and healthcare team about the benefits and risks of taking lamotrigine.

Depending on the situation, your healthcare professional may decide to switch you to a different medication or monitor your symptoms carefully. Additionally, they might recommend testing procedures, such as an electrocardiogram, to assess your risk.

The FDA cautions not to stop taking this medication without first consulting your prescribing physician, as stopping lamotrigine can cause unmanageable seizures or worsening mental health symptoms.

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Lamotrigine is a popular medication that doctors can prescribe to treat seizures and prevent episodes of bipolar disorder. Though new data show the medication may increase the risk of arrhythmias in some individuals with heart disease, many studies to date show it doesn’t seem to affect cholesterol levels.

Every drug poses risks, and lamotrigine is no exception. It’s important to discuss any concerns you have about this medication with your doctor.