Olanzapine for maintenance treatment of bipolar disorders
Brief summary
Evidence from systematic reviews
What is the current evidence for the use of olanzapine in the maintenance treatment of bipolar disorders?
Olanzapine performs better than placebo in preventing relapses of bipolar disorder. When compared to valproate, the inconclusive results tended to favour valproate in the prevention of bipolar relapses. When compared to lithium, olanzapine performed better in the prevention of all relapses and relapse of manic episodes; lithium performed better in the prevention of depressive episodes. The results of a small study comparing olanzapine and mood stabilisers with mood stabilisers alone found that adding olanzapine to a mood stabiliser did not impact on the prevention of relapses, however, patients using the combination of a mood stabiliser and olanzapine tended to stay longer in the follow up.
All trials were sponsored by Eli Lilly, the manufacturer of Olanzapine.
Is there any group of patients that respond better to olanzapine than the others?
- Primary studies included adult outpatients, both genders, with a diagnosis of bipolar I and/or bipolar II disorder (using DSM-IV criteria).
- Patients with substance abuse within the past month, serious risk of suicide, and intolerance to olanzapine were excluded in most primary studies.
- Patients with rapid cycling were excluded in two included trials, and made up approximately 50% of subjects in the other 3 studies.
Should olanzapine be used as a single or combination treatment?
Two studies compared olanzapine with valproate, one with lithium, one with placebo, and another one compared olanzapine + mood stabilisers with mood stabilisers.
What are the adverse events at short and long term?
- There is little information provided about the adverse events at long term.
For how long should olanzapine (single or combination) be used?
- Trials used olanzapine from 6 to 18 months.
Is olanzapine more efficacious than other mood stabilisers in the maintenance treatment of bipolar disorders?
When compared to valproate, valproate was more effective in the prevention of bipolar relapses. When compared to lithium, olanzapine performed better in the prevention of all relapses and relapse of manic episodes; lithium performed better in the prevention of depressive episodes.
Is the balance between harm and benefit favourable to the use of olanzapine?
It is not clear from the systematic reviews and/or the primary studies whether the adverse effects of olanzapine outweigh the benefits.
What type of research (if any) is needed to clarify the benefits and harms of using olanzapine for maintenance treatment?
Trials should compare olanzapine with other antipsychotics or mood stabilisers: the combination of olanzapine with other mood stabilisers has been advised by guidelines, and therefore should be tested more thoroughly and conclusively.
