Panic Attack Following Addition of Nalmefene to Methylphenidate in a Patient with Comorbid Alcohol Use Disorder and Attention Deficit Hyperactivity Disorder: A Case Report

Aim: Our aim is to describe a previously unreported potential interaction of nalmefene with methylphenidate and discuss possible mechanisms and precautions. Presentation of Case: A 40-year-old man with ADHD taking long-acting methylphenidate developed alcohol use disorder. Nalmefene was prescribed. Following his first bedtime administration, he awoke with panic attack symptoms and concomitant suicidal and homicidal ideation. These symptoms resolved 45 minutes after he received diazepam. Discussion: Hypotheses for this reaction include a previously undescribed nalmefene–methylphenidate interaction causing elevated levels of either drug and leading to anxiety and panic symptoms, dysphoria, and suicidal/homicidal ideation. ADHD and alcohol abuse disorder are common comorbidities and treatment with both methylphenidate and nalmefene is a reasonable approach. Conclusions: The patient described in this case had not previously reported any of these adverse events, reported them on the first and only occasion of ingesting methylphenidate and nalmefene on the same day, and has not reported them since, suggesting that the adverse events may have been associated with a drug–drug interaction. However, our experience with this case suggests that further research is required on this potential interaction and that clinicians should be aware of this potential interaction and use caution in prescribing this combination