Lamictal (Lamotrigine)

Lamotrigine is used to control abnormal neuronal activity in several seizure types and mood disorders.

• Partial seizures: Reduces frequency and severity of focal onset seizures.
• Generalized tonic‑clonic seizures: Helps prevent convulsive seizures in patients with generalized epilepsy.
• Bipolar disorder (maintenance therapy): Stabilizes mood and decreases recurrence of depressive and manic episodes.

• Lamotrigine inhibits voltage‑gated sodium channels, which stabilizes neuronal membranes and limits the release of excitatory neurotransmitters such as glutamate. By reducing rapid neuronal firing, it diminishes the propagation of seizure activity and modulates mood‑regulating pathways, contributing to its efficacy in epilepsy and bipolar disorder maintenance. The drug also exhibits weak inhibition of calcium channels and may affect serotonin receptors, further supporting its therapeutic profile.

Lamotrigine may cause a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Headache: mild to moderate headache.
• Dizziness: sensation of light‑headedness or unsteadiness.
• Nausea: upset stomach or feeling sick.
• Rash: mild skin redness or itching.
• Insomnia: difficulty falling or staying asleep.

Serious or Rare Side Effects

• Stevens‑Johnson syndrome: severe skin reaction with blistering and mucosal involvement.
• Toxic epidermal necrolysis: life‑threatening skin detachment.
• Aseptic meningitis: inflammation of the meninges without infection.
• Blood dyscrasias: such as agranulocytosis or pancytopenia.
• Hepatotoxicity: liver enzyme elevation or liver injury.

Before initiating lamotrigine therapy, several precautions should be considered to minimize risk.

• Initiate low dose: Start with a low dose and increase gradually to reduce rash risk.
• Monitor skin reactions: Discontinue immediately if a widespread rash or signs of Stevens‑Johnson syndrome appear.
• Assess hepatic function: Use caution in patients with liver impairment and monitor liver enzymes.
• Review concomitant drugs: Certain medications (e.g., valproate) can increase lamotrigine levels and require dose adjustment.
• Pregnancy and lactation: The safety profile is unclear; discuss risks with a healthcare professional.
• Store at ambient temperature: Keep below 25 °C in the original packaging, protected from moisture.

Lamotrigine interacts with several medicines that can alter its plasma concentration or increase toxicity.

Major Interactions (Avoid)

• Valproic acid: Inhibits lamotrigine metabolism, significantly increasing its plasma concentration; dose adjustment is essential.
• Carbamazepine: Induces hepatic enzymes, markedly decreasing lamotrigine levels and possibly reducing seizure control.
• Phenobarbital: Strong enzyme inducer that lowers lamotrigine exposure, requiring careful monitoring.

Moderate Interactions (Monitor Closely)

• Oral contraceptives: Can reduce lamotrigine levels, potentially necessitating dose review.
• Sertraline: May increase the incidence of skin rash when combined with lamotrigine.
• Rifampicin: Induces metabolism and may lower lamotrigine concentrations.