The exact mechanism of action of lamotrigine is unknown. However, it is believed that lamotrigine affects chemicals in the brain involved in seizures and in bipolar disorder.
Lamotrigine is used alone or in combination with other medications in the treatment of seizures and bipolar disorder.
Before taking lamotrigine, tell your doctor if you have heart, liver, or kidney disease or other serious medical problems. You may not be able to take lamotrigine, or you may require a dosage adjustment or special monitoring during treatment.
Lamotrigine is not known to be harmful to an unborn baby. Do not take this medication without first talking to your doctor if you are pregnant or could become pregnant during treatment. Before you start breast-feeding an infant , inform your doctor. Lamotrigine passes into breast milk and may affect a nursing infant. Other symptoms that you may feel while taking lamotrigine are drowsiness, dizziness, blurred vision, or poor coordination. It is best to avoid driving, operating dangerous machinery or performing any hazardous activities that needs you to be alert and fully awake while taking Lamotrigine to prevent accidents.
It is important to take lamotrigine regularly to get the most benefit. The dose of lamotrigine must be increased slowly but it may be several weeks or months before the optimal dose can be determined. Even if you feel better, do not stop taking this medicine suddenly to prevent recurrence of symptoms. Stopping lamotrigine suddenly may result in increased seizure frequency or a return of symptoms of bipolar disorder. If the medication needs to be stopped, your doctor may need to lower the dosage gradually.
If for whatever reason you need to stop then restart taking lamotrigine, contact your doctor. A lower dose may be needed to prevent side effects from occurring. Occasionally, while undergoing lamotrigine treatment, blood tests or other medical evaluations may be needed to monitor progress and side effects.
Rarely, lamotrigine has been associated with severe and/ or life-threatening rashes and hypersensitivity reactions. Contact your doctor immediately if you develop any skin rash; fever; hives; swelling of the lips, tongue, or face; sores in the mouth or around the eyes; or swollen lymph glands. During treatment with lamotrigine, if you experience increasing frequency or worsening of seizures also seek emergency consult. .
Other, less serious side effects which may be more likely to occur include:
dizziness or drowsiness; blurred or double vision; nausea and vomiting;
headache; or lack of coordination. Report to your attending physician any other unusual side effects other than those listed here.
Symptoms of a lamotrigine overdose include dizziness, drowsiness, headache, increased seizures, and unconsciousness. Seek medical attention immediately once overdose symptoms are suspected.
Lamotrigine may interact with many other drugs used to treat seizures. To be on safe side, before taking lamotrigine, tell your doctor about all other medications you are currently taking such as over-the-counter or prescribed medications including herbal products, vitamins and minerals.
You may require a dosage adjustment or special monitoring during treatment if you are taking lamotrigine alone or with other medications to treat seizures. Use of birth control pills may decrease the amount of lamotrigine in the body. A dosage adjustment may be necessary if birth control pills are started or stopped during treatment with lamotrigine. Lamotrigine may also increase the effects of other drugs that cause drowsiness, including antidepressants, alcohol, antihistamines, sedatives (used to treat insomnia), pain relievers, anxiety medicines, and muscle relaxants. Dangerous sedation, dizziness, or drowsiness may occur if lamotrigine is taken with any of these medications.
Lamotrigine, an antiepileptic drug (AED) of the phenyltriazine class, is chemically unrelated to existing antiepileptic drugs. Its chemical name is 3,5-diamino-6-(2,3-dichlorophenyl)-as-triazine, its molecular formula is C9H7N5Cl2, and its molecular weight is 256.09. Lamotrigine is a white to pale cream-colored powder and has a pKa of 5.7. Lamotrigine is very slightly soluble in water (0.17 mg/mL at 25°C) and slightly soluble in 0.1 M HCl (4.1 mg/mL at 25°C). LAMICTAL Tablets are supplied for oral administration as 25-mg (white), 100-mg (peach), 150-mg (cream), and 200-mg (blue) tablets. Each tablet contains the labeled amount of lamotrigine and the following inactive ingredients: lactose; magnesium stearate; microcrystalline cellulose; povidone; sodium starch glycolate; FD&C Yellow No. 6 Lake (100-mg tablet only); ferric oxide, yellow (150-mg tablet only); and FD&C Blue No. 2 Lake (200-mg tablet only).
Lamotrigine has the following structural formula: