When patients with mania associated with recent antidepressant use were excluded from post hocanalysis, topiramate’s superiority over placebo was re-established. These tantalizing results require further study. Similarly, studies of topiramate’s potential efficacy in acute bipolar depression and as a maintenance treatment are needed.
Oxcarbazepine Oxcarbazepine is a relative newcomer to the United States, but has been available abroad for some time.
While numerous studies have tested carbamazepine in treating various aspects of bipolar disorder, few controlled trials have tested oxcarbazepine for this use.20
Oxcarbazepine as a treatment for acute bipolar mania was comparable to haloperidol in two small randomized, controlled trials and to lithium in one small trial. None of these studies had adequate power to detect potential differences in efficacy. Similarly, two very small maintenance studies (total N=25) found no differences in efficacy between oxcarbazepine and lithium.20
Additionally, to our knowledge oxcarbazepine has not been formally tested as a treatment for acute bipolar depression. So while oxcarbazepine is an attractive alternative to carbamazepine for pharmacokinetic and pharmacodynamic reasons, data supporting oxcarbazepine’s efficacy in bipolar disorder are far less substantial.
Zonisamide The only report of zonisamide as a bipolar disorder treatment so far is a case series of 15 patients who received the drug adjunctively for manic symptoms. Of these patients, 80% showed at least moderate improvement and 33% were rated as markedly improved. These preliminary observations require further study. Like topiramate, zonisamide may also be associated with weight loss in some patients.
Tiagabine A few case reports and case series describe tiagabine’s effects in patients with bipolar disorder. Conflicting results have been reported to date and some reports of poor tolerability have emerged. Fundamental safety and efficacy data for this agent in bipolar disorder are needed.
Levetiracetam Studies of levetiracetam for treatment of bipolar disorder are just under way. The Stanley Foundation Bipolar Treatment Network, a program of the National Alliance for the Mentally Ill Research Institute, is investigating its potential thymoleptic properties.
Related resources
- Joffe RT, Calabrese JR. Anticonvulsants in Mood Disorders. New York: Marcel Dekker Inc., 1994.
- Modigh K, Robak OH, Vestergaard P. Anticonvulsants in Psychiatry. Bristol, Pa: Wrightson Biomedical Publishing, Ltd., 1994.
- Schatzberg AF, Nemeroff CB. Textbook of Psychopharmacology, 2 nd ed. Washington, DC: American Psychiatric Press, 1998.
- Nathan P, Gorman J. A Guide to Treatments that Work, 2 nd ed. New York: Oxford University Press, 2001.
- Janicak PG, Davis JM, Preskorn SH, Ayd FJ, Jr. Principles and Practice of Psychopharmacotherapy, 2 nd ed. Baltimore, MD: Williams & Wilkins, 1997.
Drug brand names
- Carbamazepine • Tegretol, Epitol, Atretol
- Gabapentin • Neurontin
- Lamotrigine • Lamictal
- Levetiracetam • Keppra
- Oxcarbazepine • Trileptal
- Tiagabine • Gabatril
- Topiramate • Topamax
- Valproate-divalproex sodium • Depakote, Depakote ER
- Zonisamide • Zonegran
Disclosure
Dr. Keck reports that he receives grant/research support from and serves as a consultant to Abbott Laboratories, AstraZeneca, Pfizer Inc., and Eli Lilly and Co. He also receives grant/research support from Merck and Co. and Otsuka America Pharmaceutical, and serves as a consultant to Bristol-Myers Squibb Co., GlaxoSmithKline, and Janssen Pharmaceutica.
Dr. McElroy reports that she receives grant/research support from and serves as a consultant to Abbott Laboratories, Elan Pharmaceuticals, Cephalon Inc. GlaxoSmithKline, and Eli Lilly and Co. She also receives grant/research support from Forest Pharmaceuticals and Solvay Pharmaceuticals, and serves as a consultant to Bristol-Myers Squibb Co., Ortho-McNeil Pharmaceutical, and Janssen Pharmaceutica.