A Case Report of Encephalopathy With Myoclonus: A Rare Neurologic Side Effect of Ranolazine.

The evaluation of the cause of an acute encephalopathy can be challenging due to nonspecific presentations and many potential etiologies. Ranolazine-induced encephalopathy has seldom been reported in the literature. We report a case of ranolazine-induced encephalopathy with myoclonus. A 78-year-old male with past medical history of coronary artery disease (CAD) with refractory angina on ranolazine, chronic kidney disease (CKD) stage III, multiple other medical comorbidities presented to the hospital after a fall and complaints of generalized weakness. The patient, during admission, developed encephalopathy and generalized myoclonus that resolved by stopping ranolazine. Acute encephalopathy has a wide differential diagnosis. The association of myoclonus and bilateral asterixis favors a systemic metabolic process or a circulating factor. It is essential in workup that close attention be paid to medication review as patients with liver and/or kidney dysfunction can become toxic on routine medication doses. This case signifies the importance of medication review and highlights ranolazine as a potential cause of acute encephalopathy with myoclonus.