Abstract
Since introduction, lamotrigine has got excellent track record of safety and in various clinical trials has been found to induce manic/hypomanic switch no greater than placebo [1]. It was Margolese et al. who first reported that lamotrigine can cause hypomanic symptoms [2]. However, a thorough PubMed search till 20 February 2006 did not reveal a single case of severe mania induced by lamotrigine. We report one rare case of severe manic switch in an adolescent with recurrent depressive disorder induced by lamotrigine.
K.S., a 15-year-old male patient with nil contributory past or family history was first time brought for consultation in August 2004 with 3 months history suggestive of a severe psychotic depressive episode. We initiated treatment with tablet olanzapine 7.5 mg day−1 and tablet lithium which was gradually increased up to 1050 mg day−1 with serum lithium level (SLE) being 0.89 mmol L−1. He had achieved complete remission within 2 months and had been maintaining well with good compliance till July 2005 when he developed a moderate depressive episode following failure in a class examination. Initially we adjusted SLE to 0.97 mmol L−1(1200 mg day−1), but he continued to be depressed. During this episode, his thyroid function test and electroencephalogram were within normal limits. There was no history of substance intake and urinary screening for cannabinoids and opioid were negative. We added lamotrigine to lithium with a future plan of lamotrigine monotherapy in case of response. When the dose of lamotrigine reached 100 mg day−1, he became abusive, assultative, overtalkative and hyperactive. His sleep was reduced and he was found to have delusion of grandeur abilities. As the symptoms did not abate within 1 week, we discontinued lamotrigine and admitted him in our emergency ward. He was discharged with lithium 1200 mg day−1 (SLE 1.00 mmol L−1) and olanzapine 20 mg day−1. Within 1 month he became completely euthymic.
Quick emergence upon introduction and reversibility of manic symptoms following discontinuation of lamotrigine in our case establishes strong association of lamotrigine in causing a severe manic switch. This association is quite robust considering the point that K.S. did not have a positive family history of mood disorders.
Recent findings particularly indicate an independent and perhaps depression phase-specific efficacy of lamotrigine in bipolar disorders. The drug has significant antidepressant effect [3], and at the same time it is less effective in preventing a manic episode [4]. These combined together may underlie lamotrigine's propensity to cause manic switch.
In short, our case example emphasizes that even lamotrigine may induce severe manic switch and caution should be taken during its use especially in early onset unipolar recurrent depressive disorder.