When is it safe to restart Lamictal (lamotrigine) in a patient who stopped taking 200mg daily?

Restarting Lamotrigine After Discontinuation

When restarting lamotrigine 200 mg daily after discontinuation, you must follow the standard titration schedule starting at a low dose to minimize the risk of serious rash, including Stevens-Johnson syndrome.

Titration Schedule for Restarting Lamotrigine

The safest approach requires gradual dose escalation regardless of the patient's previous stable dose:

1. Week 1-2: Start with 25 mg once daily
2. Week 3-4: Increase to 50 mg once daily
3. Week 5-6: Increase to 100 mg once daily (or 50 mg twice daily)
4. Week 7 onwards: Increase to 200 mg once daily (or 100 mg twice daily)

Factors Affecting Titration Speed

• Duration of discontinuation:

  • If discontinuation was brief (less than 5 days), a more rapid titration might be considered
  • If discontinuation was longer than 5 days, the full 6-week titration schedule is mandatory

• Concomitant medications:

  • If taking valproate: Use a slower titration (start with 12.5 mg every other day)
  • If taking enzyme inducers (carbamazepine, phenytoin): May require faster titration and higher target dose

Monitoring During Restart

• Rash surveillance: Monitor closely for any skin reactions, particularly during the first 8 weeks
• Neurological symptoms: Watch for headache, dizziness, ataxia, diplopia
• Psychiatric symptoms: Monitor for mood changes, as abrupt discontinuation and restart may affect mood stability

Special Considerations

• Previous history of rash: If the patient previously developed any rash on lamotrigine, extreme caution is warranted when restarting
• Reason for discontinuation: If stopped due to adverse effects, consider alternative treatments
• Pregnancy status: Use caution in women of childbearing potential; ensure effective contraception

Common Pitfalls to Avoid

• Rushing the titration: The most dangerous error is restarting at the previous full dose (200 mg), which significantly increases risk of serious rash
• Ignoring drug interactions: Failure to adjust for medications that affect lamotrigine metabolism
• Inadequate patient education: Patients must understand the importance of reporting any rash immediately
• Discontinuing without medical supervision: Patients should be warned against abrupt discontinuation, which can lead to withdrawal symptoms and seizure risk

The standard titration schedule is recommended even for patients who previously tolerated lamotrigine well, as the risk of serious rash returns when the medication is discontinued and then restarted at a high dose.