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Lamotrigine: 7 things you should know

Medically reviewed by Carmen Fookes, BPharm. Last updated on Nov 20, 2019.

1. How it works

  • Lamotrigine is used either alone or in combination with other anticonvulsants to treat epilepsy. It may also be used to stabilize mood in people with bipolar disorder.
  • Experts are not sure exactly how lamotrigine works But some have suggested that it inhibits voltage-sensitive sodium channels, stabilizing nerve membranes and moderating the release of excitatory amino acids such as glutamate and aspartate.
  • Lamotrigine belongs to the class of medicines known as triazine anticonvulsants.

2. Upsides

  • May be used in combination with other anticonvulsants for the treatment of partial-onset seizures, primary generalized tonic-clonic seizures, and generalized seizures associated with Lennox-Gastaut syndrome. May be used as the sole therapy for treatment of partial onset seizures.
  • May be used as maintenance treatment and to stabilize mood and delay the occurrence of depression, mania, hypomania, or mixed episodes of bipolar I disorder.
  • Blood levels of lamotrigine do not require monitoring.
  • Generic lamotrigine is available.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Dizziness, coordination problems, sleepiness, headache, double or blurred vision, nausea, vomiting, and rash. Risk of side effects increases at higher dosages and with concomitant carbamazepine.
  • Rarely, life-threatening skin rashes that require hospitalization and discontinuation of lamotrigine treatment. The risk is higher in younger children and possibly with higher lamotrigine dosages or co-administration with valproate. Most, but not all, cases occur within two to eight weeks of treatment initiation. Lamotrigine may also cause a benign, non-problematic rash and distinguishing between different rashes caused by lamotrigine may be difficult. Seek urgent medical advice at first sign of a rash with lamotrigine, unless the rash is clearly not drug-related. Discontinuation of lamotrigine may be needed.
  • Rarely, hemophagocytic lymphohistiocytosis (a life-threatening immune system syndrome) or potentially fatal hypersensitivity reactions leading to organ failure may also occur. Seek medical advice with any sign of rash, fever or swollen lymph nodes. Use of lamotrigine also increases the risk of aseptic meningitis.
  • As with other anti-epileptics, lamotrigine may increase the risk of suicidal thoughts or behavior; monitor for worsening depression or mood changes.
  • May interact with several drugs including other anticonvulsants (such as carbamazepine and phenytoin), estrogen-containing oral contraceptives, and some HIV antivirals.
  • Rarely, has been associated with sudden unexplained death.
  • Caution may be needed when using in people with renal or hepatic impairment and some other medical conditions.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

Lamotrigine is used to decrease the frequency and severity of seizures in some types of epilepsy and also to stabilize mood in bipolar disorder. Rarely, lamotrigine may cause a potentially fatal rash requiring immediate drug discontinuation.

5. Tips

  • May be taken with or without food. If you develop a stomach upset after taking lamotrigine, taking it with food may help.
  • Visually inspect your lamotrigine tablets to verify that they are indeed lamotrigine, as this drug has been associated with a number of dispensing errors. Always check with your pharmacist if you have any cause for concern.
  • Chewable and dispersible tablets are available. Chew tablets with a small amount of water or juice to aid swallowing; dispersible tablets may be dispersed in either water or diluted fruit juice. Do not attempt to administer partial quantities of the dispersed tablets. Swallow extended-release tablets whole; do not crush or chew.
  • Take exactly as directed by your doctor. Do not stop taking lamotrigine suddenly without your doctor's advice because withdrawal seizures may occur. The dosage will need tapering off on discontinuation as directed by your doctor.
  • May cause drowsiness and affect your ability to drive or operate machinery. Avoid alcohol, because alcohol may make these symptoms worse.
  • Seek urgent medical advice if you develop a severe rash or reaction after taking lamotrigine. Symptoms may include red, swollen, blistered, or peeling skin (with or without fever); red or irritated eyes; or sores in your mouth, throat, nose, or eyes. The risk of a severe skin reaction is greater in children aged 2 to 17 years; when taken in conjunction with valproate, with higher dosages of lamotrigine, or if the dosage of lamotrigine is increased too fast.
  • The extended-release form of lamotrigine (Lamictal XR) should only be used in adults and children aged 13 years or older. The immediate release form (Lamictal, Lamictal ODT) can be used in children aged 2 years or older as long as it is used in combination with other seizure medications. When used alone, this form can only be used in adults and teenagers over the age of 16.
  • May interfere with some hormonal contraceptives. Let your doctor know if you are taking birth control.

6. Response and Effectiveness

  • Lamotrigine is rapidly absorbed and peak levels are reached within 1.5 to 4.8 hours of administration.
  • The effects of lamotrigine last for over 24 hours, and once-daily dosing is often prescribed. However, some doctors prefer to split the dose to decrease the risk of side effects such as drowsiness.

7. Interactions

Medicines that interact with lamotrigine may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with lamotrigine. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with lamotrigine include:

  • estrogen-containing oral contraceptives
  • anticonvulsants such as carbamazepine, phenytoin, and phenobarbitone
  • HIV medications such as indinavir and ritonavir
  • medications that cause drowsiness, such as benzodiazepines, sedating antihistamines, and sleeping pills
  • metformin
  • opioid analgesics such as fentanyl, oxycodone, and morphine
  • rifampin
  • tramadol
  • trazodone
  • valproate.

Alcohol may worsen the side effects of lamotrigine such as drowsiness, dizziness, and liver toxicity.

Note that this list is not all-inclusive and includes only common medications that may interact with lamotrigine. You should refer to the prescribing information for lamotrigine for a complete list of interactions


Lamotrigine. Revised 06/2019.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use lamotrigine only for the indication prescribed.

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