Ranolazine toxicity precipitating seizure in the elderly

An 80+ year old woman with stage III chronic kidney disease presented after having an episode of sudden stiffening, shaking and confusion. This was the third such episode that the patient had in the past 4 weeks, and the patient has never had such an episo de previously. Of note, she was prescribed ranolazine for chronic angina 6 weeks prior. She initially started taking 500 mg two times per day which was subsequently increased to 1000 two times per day. Laboratory work up revealed an elevated creatinine of 2.42 compared with baseline of 1.9. Imaging studies revealed no acute findings suggestive of stroke. Electroencephalogram demonstrated seizure activity, and lacosamide 100 mg two times per day was prescribed. During her hospital stay, ranolazine was discontinued and the patient gradually returned to her mental baseline. This case demonstrates ranolazine toxicity that manifests as new-onset epilepsy which is more likely to occur in the elderly and patients with renal dysfunction.