Can I increase Lamictal (lamotrigine) from 100mg daily to 200mg daily for a patient who has been on 100mg for over a month?

Lamotrigine Dose Increase from 100mg to 200mg

Yes, you can safely increase lamotrigine from 100mg daily to 200mg daily for a patient who has been on 100mg for over a month, as this follows appropriate titration protocols to minimize risk of serious adverse effects.

Rationale for Dose Increase

• Lamotrigine requires gradual dose titration to reduce the risk of serious rash, including Stevens-Johnson syndrome
• A patient who has been stable on 100mg daily for over a month has completed the initial titration period
• The target dose of 200mg daily is within the standard therapeutic range for most indications

Dose Titration Protocol

When increasing from 100mg to 200mg daily:

1. Increase by 50mg increments weekly:

   • Week 1: 100mg daily → 150mg daily
   • Week 2: 150mg daily → 200mg daily

2. Consider splitting the dose into twice daily administration when reaching 200mg to improve tolerability

Special Considerations

Concomitant Medications

• If the patient is taking valproic acid, use a slower titration schedule as valproic acid significantly increases lamotrigine levels 1
• If the patient is taking enzyme-inducing antiepileptics (carbamazepine, phenytoin), faster titration may be possible

Monitoring Requirements

• Monitor for adverse effects during dose increase:

  • Skin rash (most critical adverse effect to monitor)
  • Headache, dizziness, diplopia, ataxia, nausea
  • Changes in mood or behavior

• Laboratory monitoring:

  • Baseline CBC and liver function tests before dose increase
  • Repeat testing 4 weeks after reaching the target dose 1

Adverse Effects to Watch For

• Serious rash (including Stevens-Johnson syndrome) - risk is 0.1% in bipolar disorder patients 2
• Common side effects: headache, nausea, infection, insomnia 2
• CNS effects: dizziness, ataxia, diplopia, blurred vision 3

Patient Education

Instruct patients to report immediately:

• Any skin rash (even mild)
• Fever or flu-like symptoms
• Unusual bruising or bleeding
• Visual disturbances or coordination problems
• Worsening mood symptoms

Common Pitfalls to Avoid

1. Increasing dose too rapidly - This significantly increases the risk of serious rash
2. Failure to adjust for drug interactions - Especially with valproic acid which requires lower lamotrigine doses
3. Overlooking new medications - Adding or removing medications that affect lamotrigine metabolism requires dose adjustment
4. Inadequate monitoring - Failure to monitor for adverse effects during titration period

The 100mg to 200mg increase is well-supported by clinical evidence and is generally well-tolerated when done gradually over a 2-week period in patients who have already demonstrated tolerance to lamotrigine at 100mg daily for at least one month.