What about the newer anticonvulsants? There is very little information available regarding their use in BD. Ryback et al. (1997) completed a retrospective study of 18 adolescents. Fifteen of the adolescents were diagnosed with BD not otherwise specified, one with bipolar II and two with schizoaffective disorder, bipolar type. These adolescents had failed prior mood stabilizers and were treated with gabapentin(Drug information on gabapentin) (Neurontin) in doses ranging from 900 mg/day to 2400 mg/day. Sixteen of the adolescents showed cessation of cycling, and six had improved mood. Two adolescents stopped taking gabapentin because of side effects. One adolescent experienced sedation, and the other developed rapid mood swings and irritability with methylphenidate(Drug information on methylphenidate) (Ritalin).
To date, there are no published studies of the other new antiepileptic medications, such as lamotrigine(Drug information on lamotrigine) (Lamictal), topiramate(Drug information on topiramate) (Topamax), tiagabine(Drug information on tiagabine) (Gabitril) or vigabatrin(Drug information on vigabatrin) (Sabril), in treating childhood BD. Of these agents, lamotrigine is the most problematic, given that there is a 10% incidence of rash in children, with some cases being life threatening. Exceeding initial dose recommendations and concurrent administration of valproate acid increases the risk of rash.
At present, the novel antipsychotics have been used as adjunctive treatment for childhood BD. In an open study, seven adolescents with BD received olanzapine(Drug information on olanzapine) (Zyprexa), mean daily dose 11 mg, as adjunctive treatment (Soutullo et al., 1999). Seventy-one percent of subjects showed marked to moderate response. Sedation was the most common side effect.
A retrospective chart review was completed of 28 outpatient children and adolescents with BD who received risperidone(Drug information on risperidone) (Risperdal) mean daily dose 1.7 mg as adjunctive treatment (Frazier et al., 1999). Of these adolescents, 82% were reported to be improved. The most commonly reported side effects were weight gain and sedation.
There is a single case report of an open trial of the calcium channel blocker nimodipine(Drug information on nimodipine) (Nimotop) in the treatment of an adolescent with refractory ultradian rapid cycling (Davanzo et al., 1999). After receiving nimodipine 180 mg/day for nine days, there was a significant decrease in rapid mood changes. Remission of symptoms persisted on continued treatment at 36-month follow-up. No significant side effects were reported.
Much more controlled data regarding efficacious treatment for childhood BD are necessary. Until further studies are conducted, lithium(Drug information on lithium), divalproex and carbamazepine(Drug information on carbamazepine) remain the mainstay of treatment. In cases of treatment-resistant bipolar disorder, gabapentin or adjunctive treatment with novel antipsychotics can be considered. Electroconvulsive therapy is also a treatment option for medication nonresponders.
Before initiating pharmacotherapy, however, it is necessary to educate parents about what we know and do not know about these treatments. An important component of the informed consent process is to make parents aware that, although these medications are commonly prescribed to treat childhood BD, at present there is very little scientific investigation of their effects on children and adolescents. Most studies showing these medications to be effective and safe have been conducted on adults with BD. Knowing this, parents share in the uncertainty of the outcome of the medication in their child and can view prescription of the medication as a medication trial. If the child does not respond to a medication at maximal tolerable doses, then another medication trial could be initiated.