Lamotrigine — NZ Medication Guide
📋 Reviewed by a Registered Pharmacist NZ — This information is for general educational purposes only and does not replace professional medical advice. Always consult your doctor or pharmacist before starting, stopping, or changing any medication.
What is Lamotrigine?
Lamotrigine is a broad-spectrum anticonvulsant used for epilepsy and bipolar disorder. This medication is funded by Pharmac under Special Authority for epilepsy and bipolar I disorder.
What is Lamotrigine Used For?
Used for focal seizures, generalised tonic-clonic seizures, absence seizures, Lennox-Gastaut syndrome, and prevention of depressive episodes in bipolar disorder.
How Does Lamotrigine Work?
Inhibits voltage-gated sodium channels, stabilising neuronal membranes and reducing excitatory neurotransmitter (glutamate, aspartate) release — inhibiting seizure spread.
How to Take Lamotrigine
Must be started at a very low dose and titrated over 8–12 weeks to reduce serious skin reaction risk. Maintenance: 100–200 mg/day (monotherapy). Valproate halves the required dose; enzyme inducers double it. Never increase faster than recommended.
Common Side Effects of Lamotrigine
- Headache
- Dizziness
- Double vision (diplopia)
- Rash (common — must be evaluated urgently)
- Nausea
- Insomnia
Serious Side Effects — Seek Medical Attention
Contact your doctor or call 111 immediately if you experience any of the following:
- Stevens-Johnson syndrome/TEN (life-threatening — stop immediately if extensive rash develops and seek emergency care)
- Aseptic meningitis
- Multiorgan failure (rare)
Drug Interactions
Lamotrigine may interact with other medicines. Always inform your doctor and pharmacist of all medications you are taking. Key interactions include:
- Sodium valproate (doubles lamotrigine levels — halve the lamotrigine dose)
- Carbamazepine, phenytoin (reduce levels — require higher doses)
- Combined oral contraceptive (reduces lamotrigine levels during active pills; rises during pill-free week — affects seizure control and side effects)
New Zealand Prescribing Information
Lamotrigine (25 mg, 50 mg, 100 mg, 200 mg tablets — Lamictal® and generics) is funded under Special Authority. Slow titration is critical. Any new rash requires urgent review.
Frequently Asked Questions
What should I do if I develop a rash on lamotrigine?
Contact your doctor immediately — any rash in the first 2–8 weeks requires same-day medical review. While most rashes are benign, Stevens-Johnson syndrome is life-threatening and requires prompt cessation.
Is lamotrigine safe in pregnancy?
It is among the safer antiepileptic medicines in pregnancy (lower malformation rates than valproate). However clearance increases significantly during pregnancy, requiring dose adjustments — discuss with your neurologist.
⚠️ Disclaimer: This page is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or a qualified health provider. In New Zealand, medication availability and funding may vary — check with Pharmac or your pharmacist for current information.
Reviewed by a Registered Pharmacist NZ
References & Further Information
The following New Zealand and international resources were used to inform this page: