Lamictal is available in the following formulations:
- 25 mg tablets
- 100 mg tablets
- 150 mg tablets
- 200 mg tablets
The usual dosage of Lamictal is 0.5 mg/kilogram of body weight per day initially. Lamictal can be increased very slowly (over weeks) to a maximum dosage of 5-15mg/kilogram of body weight per day. Lamictal is usually taken twice a day.
Therapeutic Drug Levels
The value of monitoring blood levels of Lamictal is not yet established.
All drugs have side effects. The most common side effects associated with the use of Lamictal include dizziness, incoordination, sleep problems, headache, double or blurred vision, nausea, vomiting and rash. Most of these symptoms are dose related, and may resolve with a lesser dose. Other rare side effects include abnormal thinking, nervousness and weight gain. A serious rash has occurred in 5-10% of patients taking Lamictal. This is a particular problem for patients taking both Lamictal and Depakote (valproic acid) concurrently.
Toxic symptoms are symptoms experienced when the blood Lamictal level is too high. Toxic symptoms can include drowsiness, incoordination, slurred speech, dizziness, headache and coma.
While children taking Lamictal do not require specific labs, your child will likely be on other anticonvulsant medications that may require occasional blood work.
Drug Interactions: Lamictal may interact with other drugs, including other antiepileptic drugs, especially Depakote. Inform your neurologist if your child is taking any other medications. Your pharmacist can often tell you if there are any known drug interactions between the medications your child takes.
Shelly Flynn, RN, MA, CPNP and Pediatric Neurology Staff
Peer Review Status: Internally Peer Reviewed
First Published: October 1998
Last Revised: October 1998