Lamotrigine, an antiepileptic drug (AED) of the phenyltriazine class, is chemically unrelated to existing antiepileptic drugs. Its chemical name is 3, 5-diamino-6-(2,352 dichlorophenyl)-as-triazine, its molecular formula is C9H7N5Cl2, and its molecular weight is 256.09. Lamotrigine is a white to pale cream-colored powder and has a pKa of 5.7. Lamotrigine is very slightly soluble in water (0.17 mg/mL at 25°C) and slightly soluble in 0.1 M HCl (4.1 mg/mL at 25°C)
Lamotrigine belongs to a group of medicines called “anti-epileptic drugs”. It is used to treat epilepsy in adults and children aged 2 years and over. Usually lamotrigine is used in addition to other medicines for the treatment of epilepsy. Lamotrigine is used in partial seizures (seizures that affect only one part of the brain) or generalised seizures (seizures that affect the whole brain), including Lennox-Gastaut Syndrome (a severe form of epilepsy characterised by several seizure types).
Immediate release: Adjunctive therapy in the treatment of generalized seizures of Lennox-Gastaut syndrome, primary generalized tonic-clonic seizures, and partial seizures; conversion to monotherapy in patients with partial seizures who are receiving treatment with a single antiepileptic drug (AED) (specifically carbamazepine, phenytoin, phenobarbital, primidone, or valproic acid); maintenance treatment of bipolar I disorder
Extended release: Adjunctive therapy for primary generalized tonic-clonic seizures and partial seizures (with or without secondary generalization); conversion to monotherapy in patients with partial seizures who are receiving treatment with a single antiepileptic drug AED
Immediate release: Adjunctive therapy for epilepsy uncontrolled by conventional therapy; monotherapy of epilepsy following withdrawal of concurrent antiepileptic agents; adjunctive therapy for Lennox-Gastaut syndrome
When you must not take it
• You are hypersensitive to, or have had an allergic reaction to, lamotrigine or any of the ingredients listed at the end of this leaflet.
Symptoms of an allergic reaction may include: cough, shortness of breath, wheezing or difficulty breathing; swelling of the face, lips, tongue, throat or other parts of the body; rash, itching or hives on the skin; fainting; or hay fever-like symptoms.
If you think you are having an allergic reaction, do not take any more of the medicine and contact your doctor immediately or go to the Accident and Emergency department at the nearest hospital.
• It has passed the expiry date (EXP) printed on the pack.
• The packaging is torn, shows signs of tampering or it does not look quite right.
Warnings and precautions
Talk to your doctor, pharmacist or nurse before taking Lamotrigine tablets
• If you have any kidney problems.
• If you have ever developed a rash after taking lamotrigine or other medicines for bipolar disorder or epilepsy.
• If you have ever developed meningitis after taking lamotrigine
• If you are already taking medicine that contains lamotrigine.
Brugada syndrome is a genetic disease that results in abnormal electrical activity within the heart. ECG abnormalities which may lead to arrhythmias (abnormal heart rhythm) can be triggered by lamotrigine. Talk to your doctor, if you have this condition.
Haemophagocytic lymphohistiocytosis (HLH)
There have been reports of a rare but very serious immune system reaction, in patients taking lamotrigine.
Contact your doctor or pharmacist immediately if you experience any of the following symptoms while taking lamotrigine: fever, rash, neurological symptoms (e.g. shaking or tremor, confusional state, disturbances of brain function).
If any of these applies to you, please tell your doctor, who may decide to lower the dose, or decide whether Lamotrigine tablets is suitable for you or not.
Pregnancy and Breast-feeding
Contact your doctor if you are pregnant or might become pregnant or planning to become pregnant. It’s important that you do this because there may be an increased risk of birth defects in babies whose mothers took Lamotrigine during pregnancy.
These defects include cleft lip or cleft palate. Your doctor may advise you to take extra folic acid if you’re planning to become pregnant and while you’re pregnant. Pregnancy may also alter the effectiveness of Lamotrigine, so your doctor may take samples of your blood to check the level of Lamotrigine, and may adjust your dose.
Talk to your doctor if you’re breast feeding or planning to breast feed.
If you are breast-feeding or planning to breast-feed ask your doctor or pharmacist for advice before taking this medicine. The active ingredient of Lamotrigine passes into breast milk and may affect your baby. Your doctor will discuss the risks and benefits of breast-feeding while you’re taking lamotrigine, and will check your baby from time to time, whether drowsiness, rash or poor weight gain occurs, if you decide to breast-feed.
Inform your doctor if you observe any of these symptoms in your baby.
Lamotrigine passes into breast milk and may affect your baby. Your doctor will discuss the risks and benefits of breast feeding while you’re taking Lamotrigine, and will check your baby from time to time if you decide to breast feed.
Driving and using machines
Lamotrigine tablets can cause dizziness and double vision. Don’t drive or operate machines unless you are sure you’re not affected.
Lamotrigine Tablets contains lactose
This medicine contains small amounts of an inactive ingredient known as Lactose monohydrate. If you have been told by your doctor that you have an intolerance to some sugars, contact your doctor before taking Lamotrigine tablets.
How to take Lamotrigine Tablets
The usual effective dose of Lamotrigine for adults and children aged 13 years or over is between 100 mg and 400 mg each day. For children aged 2 to 12 years, the effective dose depends on their body weight – usually, it’s between 1 mg and 15 mg for each kilogram of the child’s weight, up to a maximum of 200 mg daily. Lamotrigine tablets are not recommended for children aged under 2 years.