Anticonvulsant effect may be due to presynaptic inhibition of glutamate release. Efficacious as adjunctive therapy for partial seizures (with or without secondary generalization) and Lennox-Gastaut syndrome. Preliminary data suggest it may also be useful as an adjunct for refractory generalized seizures, or as monotherapy for newly diagnosed partial or generalized seizures.25 Also FDA approved for bipolar disorder.

The standard for generalized epilepsies (GE) monotherapy in treatment is valproic acid (VPA) and lamotrigine (LTG) has been proposed as an alternative to VPA.

A meta-analysis suggests that VPA appears to be a better choice in controlling seizure following generalized epilepsy (GE). However, therapy should be switched to alternative monotherapy if an adequate trial of VPA monotherapy is not effective and intolerable, especially in young women 1).

Somnolence, dizziness, diplopia. ✖ Serious rashes requiring hospitalization and discontinuation of therapy have been reported (rash usually begins 2 weeks after initiating therapy and may be severe and potentially life-threatening, including Stevens-Johnson syndrome (more of a concern with simultaneous use of valproate), and rarely, toxic epidermal necrolysis (TEN)). Incidence of significant epidermal reaction may be decreased by a slow ramping-up of dosage. May increase seizure frequency in some patients with severe myoclonic epilepsy of infancy. Metabolism of lamotrigine is affected by concurrent use of other AEDs.

In neurology, psychiatry, and neurosurgery, several human leukocyte antigen (HLA) alleles have been reportedly associated with cutaneous adverse drug reactions (cADRs) induced by antiepileptic drugs, which significantly carry the risk of developing cADRs. Prior to using antiepileptic drugs such as carbamazepine and lamotrigine, which are prone to cause severe cADRs, preemptive HLA genetic testing and therapeutic interventions such as drug selection and dosage adjustment based on the results of the tests can reduce the incidence of cADRs in the population before the initiation of treatment 2).

℞ Adult: In adults receiving enzyme-inducing AEDs (PHT, CBZ, or phenobarbital), start with 50mg PO q d x 2 wks, then 50mg BID× 2 wks, then ↑ by 100mg/d q week until the usual maintenance dose of 200–700mg/d (divided into 2 doses) is reached. For patients on valproic acid (VA) alone, the maintenance dose was 100–200mg/d (divided into 2 doses), and VA levels drop by ≈ 25% within a few weeks of starting lamotrigine. For patients on both enzyme-inducing AEDs and VA, the starting dose is 25mg PO qod × 2 wks, then 25mg qd × 2 wks, then ↑ by 25–50mg/d q 1–2 wks up to a maintenance of 100–150mg/d (divided into 2 doses). Instruct patients that rash, fever or lymphadenopathy may herald a serious reaction and that a physician should be contacted immediately. Peds: not indicated for use in patients < 16 yrs old due to higher incidence of potentially life-threatening rash in the pediatric population.23 Supplied: 25, 100, 150 & 200mg tablets. 2, 5 & 25mg chewable dispersible tablets.

Tang L, Ge L, Wu W, Yang X, Rui P, Wu Y, Yu W, Wang X. Lamotrigine versus valproic acid monotherapy for generalised epilepsy: A meta-analysis of comparative studies. Seizure. 2017 Aug 12;51:95-101. doi: 10.1016/j.seizure.2017.08.001. [Epub ahead of print] Review. PubMed PMID: 28826049.
Mushiroda T. Avoidance of cutaneous adverse drug reactions induced by antiepileptic drugs based on pharmacogenomics. J Hum Genet. 2022 May 9. doi: 10.1038/s10038-022-01040-1. Epub ahead of print. PMID: 35534674.
  • lamotrigine.txt
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