What is the next dose to increase Lamictal (lamotrigine) from 100mg?

Lamotrigine Dose Increase from 100mg

The next dose when increasing Lamotrigine from 100mg should be 150mg. 1

Lamotrigine Titration Guidelines

Lamotrigine requires careful titration to minimize the risk of serious adverse effects, particularly rash. The appropriate titration schedule depends on several factors:

• Standard titration for patients not on interacting medications:

  • Starting at 100mg, increase to 150mg for 1-2 weeks 2
  • Then increase to 200mg (target maintenance dose) 2, 3
  • Further increases may be made in 50-100mg increments if needed 4

• For patients on valproate (which inhibits lamotrigine metabolism):

  • Slower titration is required due to increased lamotrigine levels 3
  • Smaller increments (25-50mg) are recommended 3

• For patients on enzyme-inducing medications (carbamazepine, phenytoin):

  • Faster titration may be possible 3
  • Higher target doses (up to 400mg daily) may be needed 3

Dosage Forms Available

Lamotrigine is available in various formulations:

• Immediate-release tablets: 25mg, 50mg, 100mg, 200mg 1
• Extended-release tablets: 25mg, 50mg, 100mg, 200mg, 250mg, 300mg 1

Safety Considerations

• Rash risk: The most serious concern with lamotrigine titration is the risk of severe rash, including Stevens-Johnson syndrome. Slow titration significantly reduces this risk 2, 4

• Common adverse effects to monitor:

  • Headache, dizziness, diplopia (double vision), drowsiness 4
  • These effects are typically dose-dependent and more common at higher doses 5, 4

• Pharmacokinetics:

  • Half-life: 22.8-37.4 hours in patients on lamotrigine monotherapy 3
  • Linear pharmacokinetics during long-term administration 3
  • Bioavailability of approximately 98% 3

Special Considerations

• Extended-release option: If experiencing peak-dose side effects, conversion to extended-release formulation may improve tolerability while maintaining efficacy 5

• Therapeutic plasma levels: While not routinely monitored, a range of 1-4 mg/L has been proposed as potentially therapeutic 3

  • Some studies suggest 12.7 μmol/L may be a threshold for good therapeutic response in treatment-resistant depression 6

• Concomitant medications: Dose adjustments are necessary when adding or removing medications that interact with lamotrigine metabolism 2, 3

Remember that the goal of lamotrigine titration is to reach an effective dose while minimizing adverse effects, particularly the risk of serious rash. The 150mg dose represents a safe increment from 100mg that balances efficacy with safety.