Both lamotrigine, lithium delay relapse of bipolar disorder. (Two International, Open-Label Studies).
Two international, open-label studies treated 1,315 symptomatic bipolar patients with lamotrigine and concurrent psychotropics. The 638 patients stabilized in 8-16 weeks of treatment then were randomized in a double-blind fashion to maintenance therapy with lithium, lamotrigine, or placebo for 18 months (76 weeks), with prospective plans to combine results from the two studies in a metaanalysis.
The lithium dose was 0.8-1.1 mEq in both studies. Lamotrigine was given in flexible dosing of 100-400 mg/day in one study of patients with a recent depressive episode and as a fixed dosage of 50, 200, or 400 mg/day in the other study of patients with a recent manic episode. The 50-mg data were not included in the metaanalysis by prospective design.
Both lamotrigine and lithium significantly delayed the time to treatment intervention for a new episode of depression or mania or the time to dropout from the study, compared with placebo. Differences between the lamotrigine and lithium groups in time to intervention were not significant, but more side effects were seen in patients on lithium, said Dr. Calabrese, director of the Mood Disorders Center at the University Hospital of Cleveland and professor of psychiatry at the Case Western University, Cleveland.
GlaxoSmithKline, Research Triangle Park, N.C., which makes lamotrigine, funded the study. Dr. Calabrese has no other financial relationship with the company.
After 18 months, 57% of patients on lamotrigine had not needed intervention for depression, compared with 51% of patients on lithium and 40% on placebo, he said. No intervention for a manic episode was needed in approximately 80% of patients on lithium, 65% of patients on lamotrigine, and 55% of patients on placebo.
Overall, approximately 40% of patients on either lamotrigine or lithium remained free of intervention for a mood episode by the end of the study, double the 20% intervention-free rate seen in patients on placebo, he reported in a poster presentation at the meeting, sponsored by the World Psychiatry Association.
Rates of side effects did not differ significantly between the 190 patients randomized to placebo and the 227 patients given lamotrigine. The 166 patients randomized to lithium were more likely to develop nausea (reported by 20%) or somnolence (13%), compared with patients on placebo, and more likely to develop diarrhea (19%) or tremor (14%), compared with patients in either the placebo or lamotrigine groups.
The most common reasons for stopping lithium because of side effects were nausea in 8% of patients and tremor in 5%; both rates were higher than the discontinuations for nausea or tremor seen with lamotrigine.
At the initial randomization to maintenance therapy, patients discontinued concurrent medications except for low-dose lorazepam, temazepam, oxazepam, or chloral hydrate.
Lamotrigine is a broad-spectrum antiepileptic drug under phase III investigation for the treatment of bipolar depression. It currently is approved as adjunctive therapy in adults with partial seizures, in adults or children with the generalized seizures of Lennox-Gastaut syndrome, and in adults with partial seizures being treated with an enzyme-inducing antiepileptic drug.
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|Publication:||Clinical Psychiatry News|
|Date:||Oct 1, 2002|
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