Similar effectiveness as other mood stabilizers. In mania and mixed states, hypomania, or the maintenance phase, oxcarbazepine worked as well as lithium, valproic acid, carbamazepine, and haloperidol (Vasudev A et al, Cochrane Database Syst Rev 2011;12:CD004857).
Better at augmenting lithium. In mania, oxcarbazepine outperformed carbamazepine at increasing the efficacy of lithium.
Reduction of specific symptoms. For example, oxcarbazepine reduced impulsivity and aggression in small, placebo-controlled studies of patients with and without bipolar disorder (Mattes JA, J Clin Psychopharmacol 2005;25(6):575–579).
Less likely to cause side effects. Studies have shown that in both epilepsy and bipolar disorder, oxcarbazepine is 20% less likely to produce side effects when compared to carbamazepine.
No aplastic anemia or agranulocytosis. These conditions are not seen with oxcarbazepine, but they’re both observed at a rate of 1 in 100,000 with carbamazepine.
Less potent inducer of CYP3A4. Being a potent inducer of CYP3A4, carbamazepine can render many medications, such as antipsychotics and antidepressants, ineffective. Whereas, oxcarbazepine induces CYP3A4 to an extent 50% less than that of carbamazepine. However, this no reassurance when it comes to the CYP3A4 interaction with oral contraceptives.
Similar side effects. Both medications can cause headaches, dizziness, somnolence, or nausea. Additionally, they both carry a risk of rash, Stevenson-Johnson syndrome, and elevated liver enzymes.
Emergence of transient side effects. Side effects are most likely to occur in the first 4 weeks of treatment with both medications.
Problematic studies. Many studies have been flawed for numerous reasons: small sample sizes, testing the effects of oxcarbazepine as an add-on to lithium, subject recruitment over too many research sites, lack of a placebo control, or a high percentage of subject dropping outs leading to results lacking statistical significance (Vieta E et al, Int J Neuropsychopharmacol 2008;11(4):445–452; (Wagner KD et al, Am J Psychiatry 2006;163(7):1179–1186).
Higher risk of hyponatremia. The risk of severe hyponatremia is 1.3% for oxcarbazepine vs 0.1% for carbamazepine; for mild it’s 30% vs 15%, respectively. Severe hyponatremia can lead to seizures, coma, and death.
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