Management of Missed Lamotrigine Dose in Bipolar Disorder
For a patient with bipolar disorder who has missed only 1 day of lamotrigine 200 mg daily, the best recommendation is to continue the home dose of 200 mg daily without restarting the titration process.
Rationale for Continuing Home Dose
When managing missed doses of lamotrigine in bipolar disorder, the approach depends on the duration of the missed treatment. For this 31-year-old woman who has been stable on lamotrigine 200 mg daily and olanzapine 15 mg daily but has missed only 1 day of medication, restarting at the full dose is appropriate.
Key considerations:
- Missing only 1 day of lamotrigine does not require dose reduction or retitration
- The risk of serious rash (the main concern with lamotrigine) is primarily associated with:
- Initial titration that is too rapid
- Restarting at full dose after prolonged discontinuation (typically >5 days)
Evidence-Based Approach
The approach to missed doses of medications can be guided by principles similar to those used for other medications:
For medications missed for <48 hours (as in this case), the recommendation is to take the missed dose as soon as possible and continue with the regular dosing schedule 1
Unlike some medications that require retitration after missing multiple doses, lamotrigine only requires retitration when treatment has been interrupted for a prolonged period (typically 5 days or more)
Important Clinical Considerations
When to Restart Titration
Lamotrigine titration should be restarted at 25 mg daily only when:
- Treatment has been interrupted for 5 or more days
- The patient has developed a rash
- The patient is starting lamotrigine for the first time
Risk of Rash with Lamotrigine
- The incidence of serious rash with lamotrigine treatment is approximately 0.1% in bipolar disorder studies 2
- Risk of rash is highest during initial titration, not with missed doses after stable treatment
- Slow titration over a 6-week period to reach 200 mg/day is recommended to minimize the incidence of serious rash 3, 2
Importance of Medication Adherence
- Medication adherence is critical for maintaining stability in bipolar disorder
- Missing multiple doses increases the risk of mood episode recurrence
- For this patient who has been stable on her regimen, maintaining treatment consistency is essential
Alternative Options and Why They're Not Recommended
Restarting lamotrigine taper at 25 mg daily: Unnecessary and potentially harmful as it would leave the patient undertreated for several weeks while retitrating, increasing risk of mood episode recurrence
Decreasing to lamotrigine 100 mg for 3 days then resuming 200 mg daily: Not supported by evidence for a single missed dose; this approach is overly cautious and may compromise mood stability
Switching to long-acting injectable (LAI) for improved adherence: An excessive intervention for a single missed dose due to lost medication during travel; this represents a significant treatment change that should be considered only for patients with persistent adherence issues
Follow-up Recommendations
- Educate the patient about the importance of medication adherence
- Suggest strategies to prevent future missed doses (pill organizers, medication reminders)
- Consider providing an emergency supply of medication for travel
- Schedule regular follow-up to monitor mood stability and medication adherence
By continuing the home dose of lamotrigine 200 mg daily after missing just one day, you maintain therapeutic coverage while avoiding unnecessary retitration that could lead to suboptimal treatment and potential mood destabilization.