Lamotrigine is not metabolized by CYP, and it is not an inducer or an inhibitor of CYP. It has been used uneventfully by 6 patients with acute porphyria. Side effects such as nausea and vomiting may be potentially porphyrinogenic through reduction in caloric intake.

Lamotrigine is a phenylthiazine and is chemically unrelated to other anticonvulsants.

Lamotrigine is an antiepileptic drug used in the treatment of partial seizures and primary and secondary generalised tonic-clonic seizures and seizures associated with Lennox-Gastaut syndrome. It is also used for prevention of depressive episodes in patients with bipolar disorder who experience predominantly depressive episodes. Lamotrigine is administered orally. Common adverse reactions of lamotrigine that can be confused with an acute porphyric attack are nausea and vomiting. These adverse reactions may be potentially porphyrinogenic through reduction in caloric intake.

Significant.

Lamotrigine is metabolised mainly by glucuronic acid conjugation to inactive metabolites, mainly a 2-N-glucuronideconjugate, a 5-N-glucuronide and a 2-N-methyl metabolite. It is eliminated renaly. There is no evidence that lamotrigine causes induction or inhibition of hepatic oxidative drug metabolising enzymes. Lamotrigine has shown to induce the accumulation of porphyrins in chicken embryo liver cells (Hahn 1997).

Uneventful use reported in 6 patients with acute porphyria.