Lamictal (Lamotrigine) Tablets for Epilepsy and Bipolar
Lamictal is an oral antiepileptic and mood stabiliser containing lamotrigine. It is used in adults and children for partial-onset seizures, primary generalised seizures, Lennox-Gastaut syndrome and bipolar disorder maintenance. Slow titration is essential.
- Active ingredients
- Lamotrigine
- Manufacturer
- GlaxoSmithKline
- Dosage forms
- tablet, chewable tablet, orally disintegrating tablet, extended-release tablet
- Available dosages
- 25mg, 50mg, 100mg, 200mg
- Category
- Neurological Medications
What is it?
Lamictal is the original brand of lamotrigine, marketed by GlaxoSmithKline since its approval as an antiepileptic in 1994 and for bipolar disorder maintenance in 2003. It is supplied as oral tablets, chewable tablets, orally disintegrating tablets (ODT) and extended-release tablets. Lamictal is dispensed only on prescription and is part of the World Health Organization List of Essential Medicines. Multiple authorised generics are now widely available.
Active ingredients
Each tablet contains lamotrigine as the sole active ingredient at 25mg, 50mg, 100mg or 200mg. Lamotrigine is a phenyltriazine that selectively blocks voltage-gated sodium channels, stabilising neuronal membranes and reducing the release of excitatory neurotransmitters, particularly glutamate.
Forms and dosages
Lamictal is administered orally once or twice daily, with or without food. According to the prescribing information, dose titration is critical and depends on co-administered antiepileptics. Typical adult monotherapy starts at 25mg daily for 2 weeks, then 50mg daily for 2 weeks, with subsequent increases to 100-200mg per day. When combined with valproate, slower titration and lower target doses are required. Slow titration minimises the risk of severe skin reactions.
Indications
Lamictal is approved in adults and children aged 2 years and older as adjunctive or monotherapy for partial-onset seizures, primary generalised tonic-clonic seizures and seizures associated with Lennox-Gastaut syndrome. It is also approved in adults for the maintenance treatment of bipolar I disorder, particularly to delay depressive episodes. According to international guidelines, Lamictal is one of the recommended agents in pregnancy because of its relatively favourable teratogenicity profile.
How it works
Lamotrigine selectively blocks voltage-gated sodium channels, stabilising neuronal membranes and reducing the release of excitatory neurotransmitters, particularly glutamate. The result is anticonvulsant activity in partial and generalised seizures, and mood-stabilising effects in bipolar disorder, particularly the prevention of depressive episodes. Unlike many other antiepileptics, lamotrigine does not cause significant cognitive impairment or sedation.
Frequently asked questions
Why must Lamictal be titrated slowly? ▾
Lamictal has been associated with serious skin reactions including Stevens-Johnson syndrome and toxic epidermal necrolysis, with a higher risk if the dose is escalated too quickly or if it is co-administered with valproate (which inhibits its metabolism). According to the prescribing information, Lamictal must be titrated slowly over weeks, with even slower titration when combined with valproate. Any rash during initiation requires immediate medical review.
Why does the dose of Lamictal differ when combined with valproate? ▾
Valproate strongly inhibits the glucuronidation of lamotrigine, doubling or more its plasma half-life and concentrations. According to the prescribing information, when combined with valproate, Lamictal should be initiated at lower doses, titrated more slowly and maintained at lower target doses than in monotherapy. Conversely, enzyme inducers (carbamazepine, phenytoin) decrease lamotrigine concentrations and require higher target doses.
Is Lamictal an effective mood stabiliser? ▾
Yes, particularly for the prevention of depressive episodes in bipolar I disorder. Several randomised trials and meta-analyses support its efficacy as maintenance therapy, with relatively limited efficacy for the treatment of acute manic episodes compared with lithium or quetiapine. According to international guidelines, Lamictal is recommended for bipolar maintenance, particularly in patients with predominant depressive episodes or who cannot tolerate lithium.
Is Lamictal safe in pregnancy? ▾
Lamictal has a relatively favourable teratogenicity profile compared with valproate or topiramate, with most studies showing no consistent increase in major congenital malformations at typical therapeutic doses. According to international guidelines, it is one of the recommended antiepileptics for women of childbearing potential when an antiepileptic is required, with monitoring of plasma concentrations during pregnancy because clearance increases substantially. The prescriber must individualise.
What are the main contraindications for Lamictal? ▾
Lamictal is contraindicated in known hypersensitivity to lamotrigine or its excipients. Caution is required in hepatic and severe renal impairment, in concurrent use with valproate (with mandatory dose modification), in patients with a history of rash on lamotrigine, and during pregnancy and breastfeeding (with the prescriber individualising). According to the prescribing information, the medical history must be reviewed by a clinician before any prescription.
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