Sertraline-Associated Riboflavin-Responsive Lipid Storage Myopathy: Report of Two Case.

INTRODUCTION/AIMS: Lipid storage myopathies (LSM) are rare disorders characterized by abnormal lipid accumulation in muscle fibers, commonly resulting in proximal muscle weakness and elevated creatine kinase (CK) levels. Within the category of LSM, there are various subtypes categorized by biochemical markers and genetic mutations. While LSM often is hereditary, there are ways that these myopathies can be acquired. Multiple acyl-CoA dehydrogenase deficiency (MADD) is a subtype of lipid storage myopathy associated with sertraline use. Sertraline has been linked to respiratory chain inhibition. The mainstay of treatment for MADD is high-dose riboflavin supplementation. We present two patients with acquired, sertraline-associated MADD who experienced full clinical recovery with riboflavin treatment before discontinuation of sertraline. METHODS: We describe two adult-onset patients with an acquired, sertraline-associated MADD-like disorder. RESULTS: Both patients showed clinical and serological improvement with riboflavin supplementation, even prior to sertraline discontinuation. Clinically, strength in the affected muscles returned to baseline (5/5) within 2 months. Serologically, the patients saw a 650-700 U/L decrease in CK levels (to baseline or near baseline) within 1 month and acylcarnitine profiles showed a marked decrease in medium and long-chain fatty acids within 6 months of initiating therapy. DISCUSSION: Although riboflavin therapy is often reserved for genetically confirmed patients, our findings support its efficacy in sertraline-associated, genetically negative MADD. These cases underscore the importance of recognizing medication-associated metabolic myopathies and the potential for targeted riboflavin therapy.