The Effect of Dermatologic Precautions on the Incidence of Rash With Addition of Lamotrigine in the Treatment of Bipolar I Disorder: A Randomized Trial

Objective: Prescribing recommendations specify that lamotrigine should ordinarily be discontinued at the first sign of rash, regardless of its type and severity, unless the rash is clearly not drug related. This practice helps to ensure that lamotrigine is discontinued in instances of serious rash (an event occurring in up to 0.13% of cases in bipolar clinical trials) but may lead to unnecessary discontinuation of lamotrigine for cases of nonserious rash arising from nondrug causes. Measures aimed at reducing overall occurrence of dermatologic reactions might reduce the incidence of nonserious rash leading to premature lamotrigine discontinuation. This study assessed the impact of specific instructions designed to decrease risk of dermatologic reactions, including nonserious rash, during initiation of and early treatment with lamotrigine in patients with bipolar I disorder.

Method: Outpatients with DSM-IV-diagnosed bipolar I disorder > =13 years of age at 188 sites were randomly assigned to receive Usual Care Precautions (UCP; precautions from the patient instructions in the prescribing information for reducing risk of rash including nonserious rash) or Dermatologic Precautions (DP; precautions as above [UCP] plus additional precautions intended to decrease risk of any dermatologic reaction including nonserious rash) during 12 weeks of adding open-label lamotrigine to concomitant medications. Patients with comorbid medical and psychiatric problems were not excluded unless, in the opinion of the investigators, these problems were sufficiently severe to preclude participation. Investigators and patients were blinded to which precaution group patients were randomly assigned. The primary outcome measure was the rate of rash during the treatment period. Secondary outcome measures included clinical response to lamotrigine, assessed with the investigator- and self-rated Clinical Global Impressions-Bipolar version (CGI-BP) and the Clinical Global Impressions-Efficacy Index (CGI-EI). Data were collected from August 2003 to August 2004.

Results: 867 (74%) of 1175 patients completed the study. Only 182 (15%) of 1175 patients had an adverse event leading to discontinuation of study medication or withdrawal, including 62 (5.3%) of 1175 due to nonserious rash. No serious rashes were reported during the study in either group. The incidence of nonserious rash was similarly low in patients with UCP and DP (8.8% and 8.6%, respectively). CGI-BP-Severity and -Improvement scores indicated mood improvement when lamotrigine was added to existing therapy, and CGI-EI scores at weeks 5 and 12 reflected a favorable balance between control of mood symptoms and tolerability. At both weeks 5 and 12, investigators reported that therapeutic effects of additional lamotrigine outweighed side effects in 74% of subjects.

Conclusion: UCP and DP yielded low, similar nonserious rash rates, which were marginally lower than nonserious rash rates in prior clinical trials that did not utilize DP but marginally higher than that in a prior open case series using DP. Nevertheless, the results are encouraging: in this large study reflecting real-world use, lamotrigine was well tolerated with no serious rash and low incidences of nonserious rash and discontinuation due to rash, and lamotrigine therapy was associated with clinical improvement in a heterogeneous cohort of patients with bipolar I disorder.