Last reviewed 2026-04-20 · How we verify

Lamictal (lamotrigine)

Lamotrigine (Lamictal), marketed by GSK, is a well-established adjunctive therapy for epilepsy. Its key strength lies in its proven efficacy and long-standing use, supported by a key composition patent expiring in 2028. The primary risk is the potential increase in generic competition following the patent expiry.

At a glance

Approved indications

• Epilepsy - Adjunctive Therapy
• Epilepsy - Monotherapy
• Bipolar Disorder - Maintenance Treatment

Boxed warnings

• WARNING: SERIOUS SKIN RASHES Lamotrigine can cause serious rashes requiring hospitalization and discontinuation of treatment. The incidence of these rashes, which have included Stevens-Johnson syndrome, is approximately 0.3% to 0.8% in pediatric patients (aged 2 to 17 years) and 0.08% to 0.3% in adults receiving lamotrigine. One rash-related death was reported in a prospectively followed cohort of 1,983 pediatric patients (aged 2 to 16 years) with epilepsy taking lamotrigine as adjunctive therapy. In worldwide postmarketing experience, rare cases of toxic epidermal necrolysis and/or rash-related death have been reported in adult and pediatric patients, but their numbers are too few to permit a precise estimate of the rate. Other than age, there are as yet no factors identified that are known to predict the risk of occurrence or the severity of rash caused by lamotrigine. There are suggestions, yet to be proven, that the risk of rash may also be increased by (1) coadministration of lamotrigine with valproate (includes valproic acid and divalproex sodium), (2) exceeding the recommended initial dose of lamotrigine, or (3) exceeding the recommended dose escalation for lamotrigine. However, cases have occurred in the absence of these factors. Nearly all cases of life-threatening rashes caused by lamotrigine have occurred within 2 to 8 weeks of treatment initiation. However, isolated cases have occurred after prolonged treatment (e.g., 6 months). Accordingly, duration of therapy cannot be relied upon as means to predict the potential risk heralded by the first appearance of a rash. Although benign rashes are also caused by lamotrigine, it is not possible to predict reliably which rashes will prove to be serious or life threatening. Accordingly, lamotrigine should ordinarily be discontinued at the first sign of rash, unless the rash is clearly not drug related. Discontinuation of treatment may not prevent a rash from becoming life threatening or permanently disabling or disfiguring [see Warnings and Precautions (5.1) ]. WARNING: SERIOUS SKIN RASHES See full prescribing information for complete boxed warning. Cases of life-threatening serious rashes, including Stevens-Johnson syndrome and toxic epidermal necrolysis, and/or rash-related death have been caused by lamotrigine. The rate of serious rash is greater in pediatric patients than in adults. Additional factors that may increase the risk of rash include: coadministration with valproate. exceeding recommended initial dose of lamotrigine. exceeding recommended dose escalation for lamotrigine. ( 5.1 ) Benign rashes are also caused by lamotrigine; however, it is not possible to predict which rashes will prove to be serious or life threatening. Lamotrigine should be discontinued at the first sign of rash, unless the rash is clearly not drug related. ( 5.1 )

Common side effects

• dizziness
• headache
• diplopia
• ataxia
• nausea
• blurred vision
• somnolence
• rhinitis
• pharyngitis
• rash
• vomiting
• infection

Drug interactions

• Estrogen-containing oral contraceptive preparations (30 mcg ethinylestradiol and 150 mcg levonorgestrel)
• Carbamazepine
• Lopinavir/ritonavir
• Atazanavir/ritonavir
• Phenobarbital/Primidone
• Phenytoin
• Rifampin
• Valproate

Key clinical trials

• A Double-Blind, Placebo-Controlled, Add-On Clinical Trial of the Safety, Pharmacokinetics and Efficacy of Lamictal in Pediatric Age Subjects (1-24 Months) (Phase 2)
• The Sustained Effects of Ketamine (Phase 1)
• Phase I/II Study of Intravenous Infusion of Tetra-o-Methyl Nordihydroguaiaretic Acid (EM-1421) in Subjects With Recurrent High Grade Glioma (Phase 1)
• Six Week Double Blind, Randomized Trial of Escitalopram Add On for Treatment Resistant Bipolar Depression (Phase 1)
• A Fixed-Dose Study of Lamotrigine Versus Placebo in the Long Term Prevention of Relapse and/or Recurrence of a Manic, Hypomanic, Mixed or Depressive Episode in Adult Subjects With Bipolar I Disorder (Phase 3)
• Double Blind Placebo Controlled Study of Lamictal in Acute Bipolar Depression (Phase 3)
• A Mulitcentre, Double-blind, Randomised, Fixed-dose Evaluation of the Safety and Efficacy of Lamictal (Lamotrigine) Compared to Placebo as an add-on Therapy to Lithium or Another Mood Stabiliser in th (Phase 3)
• Lamotrigine Therapy in the Treatment of Geriatric Bipolar Depression: An Evaluation of Markers of Cerebral Energy Metabolism (NA)

Patents

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Lamictal CI brief — competitive landscape report
• Lamictal updates RSS · CI watch RSS
• GSK portfolio CI