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Lamotrigine

Last updated on 12/07/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions   |   Tips   |   Where To Buy  

GENERIC NAME: Lamotrigine

CHINESE NAME: 拉莫三嗪

BRAND NAME(S) IN HONG KONG: Lamictal 利必通

DRUG CLASS: Antipsychotics, Anticonvulsants

SUB CLASS: Phenyltriazine

USED FOR: Bipolar disorder, Treatment and prevention of seizures and epilepsy

AVAILABLE DOSAGE FORMS:
– 25 mg, 50 mg, 100 mg (tablets)
– 2 mg, 5 mg, 25 mg (orodispersible tablets)

What is Lamotrigine for?

Lamotrigine belongs to a class of medications called phenyltriazine anticonvulsants. It works by balancing the chemicals in the brain, and is therefore used to treat psychotic disorders such as bipolar disorder and epilepsy.

How to use it?

Lamotrigine can be taken by mouth. It may be taken with or without food. Taking Lamotrigine with food may help to reduce gastrointestinal discomfort. The dosage for Lamotrigine varies with the concurrent use of adjunctive medications used, especially valproates, e.g. Valproic acid or Valproate Sodium, and enzyme-inducing anticonvulsants, e.g. Carbamazepine, Phenytoin, Phenobarbital and Primidone.

The oral dosages for Lamotrigine are listed below.

Bipolar disorder
The maximum dosage is 200 mg daily.
Adult
Monotherapy or adjunctive without valproate and enzyme-inducing anticonvulsants: Initially 25 mg once daily for 2 weeks, then 50 mg daily in 1 or 2 divided doses for 2 weeks, then 100 mg daily in 1 or 2 divided doses for 1 week, then increase to a target dose of 200 mg daily.
Adjunctive with enzyme-inducing anticonvulsants and without valproate:
Initially 50 mg once daily for 2 weeks, then 50 mg twice daily for 2 weeks, then 100 mg twice daily for 1 week, then 150 mg twice daily for 1 week, then increase to a target dose of 400 mg daily.
Adjunctive with valproate:
25 mg every other day for 2 weeks, then 25 mg once daily for 2 weeks, then 50 mg daily in 1 or 2 divided doses for 1 week, then increase to a target dose of 100 mg daily.

Epilepsy
Adult
Monotherapy or adjunctive without valproate and enzyme-inducing anticonvulsants: Initially 25 mg once daily for 2 weeks, then 50 mg once daily for 2 weeks, then increase by 50-100 mg daily every 1-2 weeks. Maintenance dose is 100-200 mg daily.
Adjunctive with enzyme-inducing anticonvulsants and without valproate:
Initially 50 mg once daily for 2 weeks, then 50 mg twice daily for 2 weeks, then increase by a maximum of 100 mg daily every 1-2 weeks. Maintenance dose is 200-400 mg daily.
Adjunctive with valproate:
Initially 25 mg every other day for 2 weeks, then 25 mg once daily for 2 weeks, then increase by 25-50 mg daily every 1-2 weeks. Maintenance dose is 100-200 mg daily.
Child over 12 year
Same as adult dose, however Lamotrigine should not be given if the calculated daily dose is <1 mg.
Child 2-12 year
Monotherapy or adjunctive without valproate and enzyme-inducing anticonvulsants: Initially 0.3 mg/kg body weight daily for 2 weeks, then 0.6 mg/kg daily for 2 weeks, then increase by a maximum of 0.6 mg/kg daily every 1-2 weeks. Maintenance dose is 1-15 mg/kg daily for monotherapy, or 1-10 mg/kg daily for adjunct therapy. Doses should be given as a single or in 2 divided doses. The maximum dosage is 200 mg daily.
Adjunctive with enzyme-inducing anticonvulsants and without valproate:
Initially 0.6 mg/kg daily in 2 divided doses for 2 weeks, then 1.2 mg/kg daily in 2 divided doses for 2 weeks, then increase by a maximum of 1.2 mg/kg every 1-2 weeks. Maintenance dose is 5-15 mg/kg daily. The maximum dosage is 400 mg daily.
Adjunctive with valproate:
Initially 0.15 mg/kg once daily for 2 weeks, then 0.3 mg/kg once daily for 2 weeks, then increase by a maximum of 0.3 mcg/kg daily every 1-2 weeks. Maintenance dose is 1-5 mg/kg daily. The maximum dosage is 200 mg daily.

What are the side effects of Lamotrigine?

Common side effects of Lamotrigine include aggression, agitation, diarrhoea, dizziness, drowsiness, dry mouth, fatigue, headache, irritability, nausea and vomiting, sleep disorders and tremor.

Who should not take Lamotrigine?

People allergic to Lamotrigine or any component of the formulation

Pharmacist Tips:

– This medication may cause drowsiness. Avoid driving or operating machinery until you know how you respond to Lamotrigine.
– Lamotrigine can induce suicidal thoughts or behaviours in patients. Report to your doctor or pharmacist if you experience these symptoms.
– This drug may cause side effects to your heart. Report any signs of abnormal heartbeat or chest pain immediately.

Common dosing schedule:
Lamotrigine is taken once or twice daily. It may be taken with or without food.

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Lamotrigine may interact with:
– Anticonvulsants, e.g. Phenobarbital, Phenytoin, Sodium Valproate
– Hormonal contraceptives, e.g. Desogestrel, Norethisterone, Levonorgestrel

Please notify your doctor or pharmacist if you are taking the above medications, dosage adjustments might be needed.

Where to buy Lamotrigine in Hong Kong?

In Hong Kong, Lamotrigine is a prescription only medicine, and requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at https://www.drugoffice.gov.hk

Need more information?

For detailed information about the use of Lamotrigine in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.