Lamogin(Lamotrigine)

Therapeutic Group: Drugs of Nervous System

Presentation

Lamogin 25: Each tablet contains Lamotrigine BP 25 mg

Lamogin 50: Each tablet contains Lamotrigine BP 50 mg

Description

The precise mechanism(s) by which lamotrigine exerts its anticonvulsant action are unknown. Lamotrigine has an effect on sodium channels. Lamotrigine inhibits voltage-sensitive sodium channels, thereby stabilizing neuronal membranes and consequently modulating presynaptic transmitter release of excitatory amino acids (e.g.glutamate and aspartate).



The mechanisms by which lamotrigine exerts its therapeutic action in bipolar disorder have not been established.

Indications

Lamotrigine is indicated for:

i)Epilepsy—adjunctive therapy in patients aged 2 years and older:

- partial-onset seizures.

- primary generalized tonic-clonic seizures.

- generalized seizures of Lennox-Gastaut syndrome

ii)Epilepsy—mono therapy in patients aged 16 years and older

iii) Bipolar disorder

Dosage & Administration

Table 1: Escalation Regimen for Lamotrigine in Patients Aged 2 to 12 Years with Epilepsy in Patients
1. Weeks 1 and 2:
• In patients taking Valproate: 25 mg every other day
• In patients not taking Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 0.15 mg/kg/day in 1 or 2 divided doses; 0.3 mg/kg/day in 1 or 2 divided doses
• In patients taking Carbamazepine, Phenytoin, Phenobarbital, or Primidone and not taking Valproate: 0.6 mg/kg/day in 2 divided doses
2. Weeks 3 and 4:
• In patients taking Valproate: 25 mg every day
• In patients not taking Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 0.3 mg/kg/day in 1 or 2 divided doses; 0.6 mg/kg/day in 2 divided doses
• In patients taking Carbamazepine, Phenytoin, Phenobarbital, or Primidone and not taking Valproate: 1.2 mg/kg/day in 2 divided doses
3. Week 5 onward to maintenance:
• In patients taking Valproate: Increase by 25 to 50 mg/day every 1 to 2 weeks
• In patients not taking Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: The dose should be increased every 1 to 2 weeks; The dose should be increased every 1 to 2 weeks
• In patients taking Carbamazepine, Phenytoin, Phenobarbital, or Primidone and not taking Valproate: The dose should be increased every 1 to 2 weeks
4. Usual maintenance dose:
• In patients taking Valproate: 100 to 200 mg/day with valproate alone 100 to 400 mg/day with valproate and other drugs that induce glucuronidation (in 1 or 2 divided doses)
• In patients not taking Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 1 to 5 mg/kg/day (maximum 200 mg/day in 1 or 2 divided doses) 1 to 3 mg/kg/day with valproate alone; 4.5 to 7.5 mg/kg/day (maximum 300 mg/day in 2 divided doses)
• In patients taking Carbamazepine, Phenytoin, Phenobarbital, or Primidone and not taking Valproate: 5 to 15 mg/kg/day (maximum 400 mg/day in 2 divided doses)

Table 2. Escalation Regimen for Lamotrigine in Patients Older than 12 Years with Epilepsy in Patients
1. Weeks 1 and 2:
• In patients taking Valproate: 0.15 mg/kg/day in 1 or 2 divided doses
• In patients not taking Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 25 mg every other day; 25 mg every day
• In patients taking Carbamazepine, Phenytoin, Phenobarbital, or Primidone and not taking Valproate: 50 mg/day
2. Weeks 3 and 4:
• In patients taking Valproate: 0.3 mg/kg/day in 1 or 2 divided doses
• In patients not taking Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 25 mg every day; 50 mg/day
• In patients taking Carbamazepine, Phenytoin, Phenobarbital, or Primidone and not taking Valproate: 100 mg/day (in 2 divided doses)
3. Week 5 onward to maintenance:
• In patients taking Valproate: The dose should be increased every 1 to 2 weeks
• In patients not taking Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: Increase by 25 to 50 mg/day every 1 to 2 weeks; Increase by 50 mg/day every 1 to 2 weeks
• In patients taking Carbamazepine, Phenytoin, Phenobarbital, or Primidone and not taking Valproate: Increase by 100 mg/day every 1 to 2 weeks.
4. Usual maintenance dose:
• In patients taking Valproate: 1 to 5 mg/kg/day (maximum 200 mg/day in 1 or 2 divided doses) 1 to 3 mg/kg/day with valproate alone
• In patients not taking Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 100 to 200 mg/day with valproate alone 100 to 400 mg/day with valproate and other drugs that induce glucuronidation (in 1 or 2 divided doses); 225 to 375 mg/day (in 2 divided doses)
• In patients taking Carbamazepine, Phenytoin, Phenobarbital, or Primidone and not taking Valproate: 300 to 500 mg/day (in 2 divided doses)

Side Effects

Common side effects of Lamotrigine include-dizziness, tremor, headache, rash, blurred vision, fever, lack of coordination, abdominal pain, infections, sleepiness, back pain, vomiting, diarrhea, tiredness, insomnia, dry mouth, stuffy nose, sore throat.

Precautions

Serious skin rashes, Blood Dyscrasias, Suicidal Behavior, Aseptic Meningitis can occur in both adult and pediatric population.

Use in Pregnancy & Lactation

Pregnancy: Pregnancy Category C.
Nursing mothers: Lamotrigine is excreted in human milk. Because of the potential for serious adverse reactions in nursing infants from Lamotrigine, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.

Pediatric Use
The safety and effectiveness of Lamotrigine in the adjunctive treatment of partial onset seizures in pediatric patients’ age 1 month to 24 months old with epilepsy have been established.