A Rare Case of Levetiracetam-Induced Refractory Hypokalemia.

Levetiracetam is a Food and Drug Administration (FDA)-approved drug for partial, generalized, and myoclonic seizures. Its mechanism of action as an antiepileptic involves the release of neurotransmitters from synaptic vesicles. The common side effects of levetiracetam include sleepiness, weakness, dizziness, and infection. We present a case of levetiracetam-induced hypokalemia, which was refractory to multiple repletion attempts. A 73-year-old woman with a history of seizures, heart failure, and previous stroke was admitted to the hospital due to witnessed seizure-like activity as a result of medication non-compliance. Her serum potassium prior to the start of antiepileptic medication was 4.5 mmol/L. She was restarted on her home dose of levetiracetam 1000 mg twice daily. Twenty-four hours after starting levetiracetam, the patient was found to have hypokalemia, and the patient's potassium levels failed to correct, dropping as low as 2.0 mmol/L despite continued repletion and normalized magnesium levels. A decision was made to switch the levetiracetam to lacosamide. Thirty-six hours after this change was made, the patient's potassium level corrected to 3.3 mmol/L and then corrected to 3.9 mmol/L five days later without requiring further repletion. Based on her clinical course, a diagnosis of levetiracetam-induced refractory hypokalemia was made. She was discharged home on lacosamide as her new antiepileptic medication, along with a close follow-up with neurology. Our case highlights the importance of considering Levetiracetam as a cause of refractory hypokalemia. Cases of levetiracetam-induced hypokalemia and hypomagnesemia are rarely reported in the literature, and those that have been reported vary greatly in onset and the resolution of electrolyte derangements. Given that levetiracetam is a widely used antiepileptic medication, we suggest that in cases of refractory hypokalemia, a change in antiepileptic medication should be considered.