Lamotrigine add‐on to valproate therapy for paediatric bipolar affective disorder

Anupam Thakur, Karuppiah Jagadheesan, Vinod Kumar Sinha, Department of Child and Adolescent Psychiatry, Central Institute of Psychiatry, Ranchi, India: Lamotrigine, a new anti-epileptic mood stabilizer, with documented therapeutic benefits for refractory bipolar disorder [1], is reported to enhance clinical improvement in bipolar affective disorder when added to valproate therapy in adults [2]. The present report reveals the clinical efficacy and safety of such combination therapy for the treatment of paediatric bipolar affective disorder. A 71/2-year-old boy, RM, presented with DSMIV bipolar affective disorder, mixed affective episode. His physical state and blood investigations were unremarkable, but electroencephalogram (EEG) showed generalized epileptiform (spike-waves) activities. He was commenced on sodium valproate 600 mg/day (20 mg/kg/day) along with olanzapine 2.5 mg/day, the latter being started for aggression. Due to lack of clinical response, at 6 weeks, lamotrigine was added to this regimen at a dose of 12.5 mg/day. The lamotrigine dose was gradually increased with 12.5 mg every 2 weeks and at 8 weeks of treatment, while on a dose of 62.5 mg/day, his symptoms remitted completely with no evidence of any adverse effects. Olanzapine was discontinued after 1 month on follow-up, and he remained symptom-free for the next 6 months. The report shows that lamotrigine add-on to sodium valproate therapy facilitated clinical remission and that this combination was well tolerated. The presence of EEG abnormalities could be considered a potential factor favouring clinical improvement with an anti-epileptic mood stabilizer therapy [3]. However, symptomatic remission in this patient, following combination therapy, suggests that the differential pharmacodynamic properties of valproate (GABA enhancer) and lamotrigine (sodium channel stabilizer) [4] could possibly have had a synergistic effect in facilitating clinical remission.