Lamogin 25mg Tablet 10pcs

Pharmacology:

The precise mechanism of action of lamotrigine is not entirely understood, but it likely involves cellular activities contributing to its effectiveness across various conditions. Though chemically distinct, lamotrigine's actions are similar to those of phenytoin and carbamazepine. It inhibits voltage-sensitive sodium channels, stabilizing neuronal membranes and modulating the release of presynaptic excitatory neurotransmitters.

Lamotrigine is believed to inhibit sodium currents by selectively binding to inactive sodium channels, thereby suppressing the release of the excitatory amino acid glutamate. This mechanism is likely consistent across both its anticonvulsant and mood-stabilizing effects. Studies have shown lamotrigine's binding to sodium channels like local anesthetics, which may also explain its benefits in certain neuropathic pain states.

Laboratory binding assays have shown lamotrigine has a weak inhibitory effect on the serotonin 5-HT3 receptor and binds weakly to several other receptors, including adenosine, adrenergic, dopamine, GABA, histamine, opioid, muscarinic, and serotonin receptors. An in vivo study suggested that lamotrigine inhibits Cav2.3 (R-type) calcium currents, potentially contributing to its anticonvulsant properties.

Overdose Effects:

Overdose can result in ataxia, nystagmus, seizures (including tonic-clonic seizures), decreased consciousness, coma, and intraventricular conduction delay.

Side Effects:

• Adults: Dizziness, headache, diplopia, ataxia, nausea, blurred vision, somnolence, pharyngitis, and rash.
• Children: Vomiting, diarrhea, infection, fever, abdominal pain, and tremor.

Dosage & Administration:

Epilepsy:

Table 1: Escalation Regimen for Patients Older Than 12 Years

Weeks 1 & 2:

• No Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 25 mg daily
• With Valproate: 25 mg every other day
• With Carbamazepine, Phenytoin, Phenobarbital, or Primidone and no Valproate: 50 mg/day

Weeks 3 & 4:

• No Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 50 mg/day
• With Valproate: 25 mg daily
• With Carbamazepine, Phenytoin, Phenobarbital, or Primidone and no Valproate: 100 mg/day (divided doses)

Week 5 onward to maintenance:

• No Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: Increase by 50 mg/day every 1-2 weeks
• With Valproate: Increase by 25-50 mg/day every 1-2 weeks
• With Carbamazepine, Phenytoin, Phenobarbital, or Primidone and no Valproate: Increase by 100 mg/day every 1-2 weeks

Usual Maintenance Dose:

• No Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 225-375 mg/day (divided doses)
• With Valproate: 100-200 mg/day alone; 100-400 mg/day with other glucuronidation-inducing drugs (divided doses)
• With Carbamazepine, Phenytoin, Phenobarbital, or Primidone and no Valproate: 300-500 mg/day (divided doses)

Table 2: Escalation Regimen for Patients Aged 2 to 12 Years

Weeks 1 & 2:

• No Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 0.3 mg/kg/day (divided doses)
• With Valproate: 0.15 mg/kg/day (divided doses)
• With Carbamazepine, Phenytoin, Phenobarbital, or Primidone and no Valproate: 0.6 mg/kg/day (divided doses)

Weeks 3 & 4:

• No Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 0.6 mg/kg/day (divided doses)
• With Valproate: 0.3 mg/kg/day (divided doses)
• With Carbamazepine, Phenytoin, Phenobarbital, or Primidone and no Valproate: 1.2 mg/kg/day (divided doses)

Week 5 onward to maintenance:

• No Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: Increase dose every 1-2 weeks to 0.6 mg/kg/day
• With Valproate: Increase dose every 1-2 weeks to 0.3 mg/kg/day
• With Carbamazepine, Phenytoin, Phenobarbital, or Primidone and no Valproate: Increase dose every 1-2 weeks to 1.2 mg/kg/day

Usual Maintenance Dose:

• No Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 4.5-7.5 mg/kg/day (max 300 mg/day, divided doses)
• With Valproate: 1-3 mg/kg/day alone; 1-5 mg/kg/day (max 200 mg/day, divided doses)
• With Carbamazepine, Phenytoin, Phenobarbital, or Primidone and no Valproate: 5-15 mg/kg/day (max 400 mg/day, divided doses)

Table 3: Initial Weight-Based Dosing Guide for Patients Aged 2 to 12 Years Taking Valproate (Weeks 1 to 4)

Weeks 1 & 2:

• 6.7-14 kg: 2 mg every other day
• 14.1-27 kg: 2 mg daily
• 27.1-34 kg: 4 mg daily
• 34.1-40 kg: 5 mg daily

Weeks 3 & 4:

• 6.7-14 kg: 2 mg daily
• 14.1-27 kg: 4 mg daily
• 27.1-34 kg: 8 mg daily
• 34.1-40 kg: 10 mg daily

Bipolar Disorder:

Table 4: Escalation Regimen for Adults

Weeks 1 & 2:

• No Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 25 mg daily
• With Valproate: 25 mg every other day
• With Carbamazepine, Phenytoin, Phenobarbital, or Primidone and no Valproate: 50 mg daily

Weeks 3 & 4:

• No Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 50 mg daily
• With Valproate: 25 mg daily
• With Carbamazepine, Phenytoin, Phenobarbital, or Primidone and no Valproate: 100 mg daily (divided doses)

Week 5:

• No Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 100 mg daily
• With Valproate: 50 mg daily
• With Carbamazepine, Phenytoin, Phenobarbital, or Primidone and no Valproate: 200 mg daily (divided doses)

Week 6:

• No Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 200 mg daily
• With Valproate: 100 mg daily
• With Carbamazepine, Phenytoin, Phenobarbital, or Primidone and no Valproate: 300 mg daily (divided doses)

Week 7:

• No Carbamazepine, Phenytoin, Phenobarbital, Primidone, or Valproate: 200 mg daily
• With Valproate: 100 mg daily
• With Carbamazepine, Phenytoin, Phenobarbital, or Primidone and no Valproate: up to 400 mg daily (divided doses)

Use in Special Populations:

• Pediatric Use:
  • Epilepsy: Safety and effectiveness for adjunctive treatment in patients aged 1 to 24 months not demonstrated.
  • Bipolar Disorder: Safety and effectiveness for maintenance treatment not established in patients aged 10 to 17 years.

Interactions:

• Valproate increases Lamogin concentrations more than two-fold.
• Carbamazepine, phenytoin, phenobarbital, primidone, and rifampin decrease Lamogin concentrations by about 40%.
• Estrogen-containing oral contraceptives reduce Lamogin concentrations by about 50%.
• Protease inhibitors lopinavir/ritonavir and atazanavir/ritonavir decrease Lamogin exposure by approximately 50% and 32%, respectively.

Pregnancy & Lactation:

• Pregnancy Category C: Lamotrigine is excreted in human milk. Due to potentially serious adverse reactions in nursing infants, decide whether to discontinue nursing or the drug, considering its importance to the mother.

Precautions & Warnings:

• Discontinue at the first sign of a rash.
• Monitor for blood dyscrasias (e.g., neutropenia, thrombocytopenia, pancytopenia).
• Monitor for suicidal thoughts or behaviors.
• Monitor for signs of aseptic meningitis.

Storage Conditions:

Store in a dry place, below 25°C, protected from light, and out of reach of children.