Olanzapine, fluoxetine combo may have edge over lamotrigine in bipolar disorder

Last Updated: 2006-08-18 18:23:32 -0400 (Reuters Health)

NEW YORK (Reuters Health) - For adults with acute bipolar I depression, the combination of olanzapine and the SSRI fluoxetine may be modestly more effective than lamotrigine, according to 7-week acute phase results of an 18-week comparative study of the two treatment approaches. The side effect profiles differ markedly, however.

In the study, investigators randomly assigned 205 patients to lamotrigine 25 mg daily titrated to 200 mg over 5 weeks as is recommended.

Another 205 started at 6 mg olanzapine and 25 mg fluoxetine (6/25). After one week, doses were increased to 12 mg olanzapine and 25 mg fluoxetine (12/25). After one day at the 12/25 dose, dosages could be adjusted to any of the following four doses: 6/25, 12/25, 6/50, or 12/50.

In the Journal of Clinical Psychiatry for July, Dr. Eileen B. Brown, from Lilly Research Laboratories in Indianapolis and colleagues report that the combination produced "statistically but modestly greater improvement" in overall severity of illness, depressive symptoms, and manic symptoms compared with lamotrigine therapy.

The incidence of treatment-emergent mania was low and not statistically significantly different between the combination and lamotrigine, whereas treatment-emergent suicidal and self-injurious behaviors occurred more often with lamotrigine than with the combination (3.4% vs 0.5%).

Somnolence, increased appetite, dry mouth, sedation, weight gain, and tremor, on the other hand, occurred more often with the combination than with lamotrigine (p < 0.05).

Weight, total cholesterol, and triglyceride levels were significantly elevated in combination-treated patients compared with lamotrigine-treated patients, with a p value of less than or equal to 0.001 for all, the investigators report.

"These increases must be considered along with potential efficacy advantages in order to make an appropriate risk/benefit assessment," Dr. Brown and colleagues write. "This must be done on an individual-patient basis."

J Clin Psychiatry 2006;67:1025-1033.