- Type of Drug: Anticonvulsant.
- Prescribed for: Lamotrigine is used as add-on therapy for adult epilepsy and partial seizures.
Lamotrigine General Information
Much like Phenytoin and Carbamazepine, Lamotrigine works on voltage-dependent channels in the brain to stabilize them and prevent the release of chemicals that can stimulate the nervous system and lead to a seizure. Lamotrigine is one of the first new antiseizure medicines available in more than 10 years.
Lamotrigine is absorbed rapidly into the bloodstream after you take it, reaching maximum blood concentration in 1 ½ to 5 hours. Lamotrigine is eliminated from the body by the liver, but the process can be affected by other drugs (see Drug Interactions).
Cautions and Warnings
During studies leading to the approval of Lamotrigine in the United States, a few people died from acute liver failure or multi-organ failure. Although all the people affected were taking Lamotrigine, it is not known if the drug played a role in these deaths.
Lamotrigine binds to melanin, a body hormone commonly found in the skin and eyes. The long-term effect of Lamotrigine on the eyes is riot known.
Lamotrigine Possible Side Effects
Lamotrigine is considered relatively safe, and its potential for producing toxic side effects is considered relatively small. Side effects are most common, during the first few weeks of treatment and tend to resolve on their own in a few weeks.
- Common: dizziness, blurred or double vision, weakness, nausea, and vomiting. These effects are related to the amount of drug in your system and so are more likely to occur with a larger daily dose.
- Other: headache, sleepiness, skin rash, and pain. Several kinds of skin rash can occur with Lamotrigine. Skin rash is more likely to occur with large doses and rapid dosage increases and may be more common in people taking Lamotrigine together with Valproate Sodium.
- Lamotrigine increases the rate at which Sodium Valproate is eliminated from the body.
- People taking both Carbamazepine and Lamotrigine may experience more drug side effects.
- Acetaminophen and Lamotrigine are broken down by the same system in the liver. Taking Acetaminophen at the same time as Lamotrigine can slightly increase the rate at which Lamotrigine is broken down, but occasional use of the two drugs together is not likely to be a problem. Regular users of Acetaminophen may need adjustment of their Lamotrigine dosage.
- Unlike other medicines for seizure control, Lamotrigine does not seem to interact with oral contraceptives.
Lamotrigine may be taken without regard to food or meals. You may take it with food or meals to prevent nausea and vomiting.
Adult and child (over age 12): 25 or 50 mg a day to start, increased gradually to a maximum daily dose of 500 mg. Lamotrigine is usually taken twice a day. Be sure to take your doses 12 hours apart.
Child (age 12 and under): not recommended.
The most likely immediate effects of Lamotrigine overdose are dizziness, blurred or double vision, weakness, nausea, and vomiting. The overdose victim should be taken to a hospital emergency room at once for treatment. ALWAYS bring the medicine bottle with you.
Lamotrigine Special Information
Once you start taking Lamotrigine, your liver may actually increase the rate at which it breaks down the drug, possibly increasing your dosage requirement. Your doctor will have to check your drug blood levels periodically to see if any dosage changes are needed.
Call your doctor at once if you develop a skin rash, but do not change your Lamotrigine dosage or stop taking it on your own.
Lamotrigine can cause drowsiness, dizziness, or blurred vision, effects that are increased by alcoholic beverages. Be careful when driving or doing anything else that requires intense concentration, alertness, and physical dexterity.
If you take Acetaminophen while on Lamotrigine (especially for a Lamotrigine-associated headache), do not take more than the amount of Acetaminophen specified in the package directions.
If you take Lamotrigine once a day and forget to take a dose, take it as soon as you remember. If it is within 8 hours of your next dose, skip the one you forgot and continue with your regular schedule. Do not take a double dose.
After the first 2 weeks of treatment, most people take Lamotrigine twice a day. If you take it twice a day, be sure to take your medicine every 12 hours. If you take Lamotrigine twice a day and forget a dose, take it as soon as you remember. If it is within 4 hours of your next dose, take one dose as soon as you remember and another in 5 or 6 hours, then go back to your regular schedule.
Lamotrigine Special Populations
Animal studies have shown no evidence of causing birth defects, but the effect of Lamotrigine on the developing human fetus is not known, A higher incidence of birth malformations has generally been noted among women with seizure disorders.
Lamotrigine passes into breast milk, but its effect on a nursing infant is unknown. If you are nursing and taking this medicine, discuss with your doctor the possibility of taking another seizure medicine or bottle-feeding your baby.
Older adults handle Lamotrigine in much the same way as younger people. You may take it in the same dosage as younger adults.