LAMOTRIGINE
(Lamictal)
Indication: Lamotrigine
is indicated for patients with complex partial seizure disorder.
Possible side effects: Among the most common side effects with
lamotrigine are dizziness, headache, blurred or double vision, lack of coordination,
sleepiness, nausea, vomiting and skin rash. Rashes are more likely to occur during
the first 6 weeks of therapy. Lamotrigine is added very slowly to prevent problems
with a rash.
If you are taking valproic acid (Depakote/Depakene), the valproic acid levels
will decrease if Lamictal is added. Also, valproic acid decreases the rate at
which the body uses lamotrigine. Therefore, the lamotrigene level can then become
two to three times higher on the same dose of lamotrigene.
You need to be aware that with any changes in your anticonvulsant therapy there
may be an increase in your seizure frequency. Also, keep in mind that side effects
vary among individuals. If you have any problems with the medication, you should
let your doctor know, whether or not it is a problem listed above.
Dosage: Lamictal is available for oral administration as 25 mg
(white), 100 mg (peach), 150 mg (cream), and 200 mg (blue) tablets. The usual
dose is between 300mg and 500mg per day.
Drug interactions: Lamotrigine inhibits dihydrofolate reductase,
an enzyme involved in folic acid synthesis. Carbamazepine, phenobarbital, phenytoin
and primidone decrease lamotrigine levels. Valproic acid decreases the clearance
of lamotrigine causing increased blood levels for lamotrigine. Other drugs can
affect, or be affected by lamotrigine.
Blood levels: The expected blood levels for lamotrigine are thought to be in the 3-20 mcg/ml range. Levels are likely to be higher when a patient is not taking other medications. It may be useful to monitor the levels of your other anticonvulsants, especially if you are taking valproic acid,when you first begin to take lamotrigine.