Off-Label Dextromethorphan/Bupropion for Emotional Lability Following Resection of an IDH-Mutant Astrocytoma: A Case Report

Pseudobulbar affect (PBA) is characterized by recurrent, involuntary episodes of crying or laughing that may be disproportionate or incongruent with an individual’s underlying mood. Although dextromethorphan/quinidine is FDA-approved for PBA, clinical experience with dextromethorphan/bupropion for this indication remains limited. We describe a 42-year-old woman with a history of resected right frontal IDH-mutant grade 2 astrocytoma who developed recurrent episodes of involuntary crying associated with emotional lability and subjective executive difficulties. At initial behavioral-health evaluation, the Center for Neurologic Study–Lability Scale (CNS-LS) score was 21/35 and the Patient Health Questionnaire-9 (PHQ-9) score was 9. The phenomenology of the crying episodes, clinical examination, neurological history, imaging surveillance, and consideration of alternative explanations supported a working clinical diagnosis of PBA, although the CNS-LS was used as a symptom measure rather than a stand-alone diagnostic test. Treatment with dextromethorphan/quinidine was associated with an initial reduction in crying episodes and CNS-LS score, followed by recurrence of symptoms. Because further treatment modification was limited by insurance coverage, an off-label trial of dextromethorphan/bupropion was subsequently initiated. Six weeks later, the CNS-LS score had decreased to 10 and the PHQ-9 score to 4. Subjective executive difficulties also improved. A temporary interruption in dextromethorphan/bupropion was followed by recurrence of crying episodes, with improvement after treatment was resumed. This case describes an association between off-label dextromethorphan/bupropion exposure and improvement in emotional-lability symptoms in a patient with a complex neurological and psychiatric presentation. The findings are hypothesis-generating and cannot establish efficacy or causality because of the single-patient design, absence of repeated CNS-LS assessments at all visits, and concomitant medication changes. Controlled studies are needed to determine whether dextromethorphan/bupropion has a therapeutic role in PBA.