Seizures associated with fluoroquinolones

To report two cases of seizures following administration of levofoxacin and ciprofloxacin.

A 75-year-old white woman admitted to the hospital was prescribed levofloxacin for ischemic toes. After receiving three doses of oral levofloxacin, the patient experienced a seizure. One month later, the patient was rechallenged with ciprofloxacin and again experienced a seizure. The patient was hypomagnesemic and had elevated serum creatinine at the time of both seizures, and was hyponatremic during the second seizure. A 74-year-old white woman admitted to the hospital was prescribed levofloxacin for bacterial pneumonia. After five doses, the patient experienced a seizure. The woman had no electrolyte imbalances at the time of the seizure and no history of a seizure disorder.

Quinolone antibiotics vary in their ability to induce seizures, with trovafloxacin having the greatest potential and levofloxacin possibly having the least potential. Neither patient had a history of a previous seizure disorder. Electrolyte imbalances are common with previous reports of fluoroquinolone-induced seizures.

Although levofloxacin monotherapy has not been implicated in inducing seizures, it appears to be the causative agent in the second case. In the first case, the quinolones may have been a necessary, but not sufficient, cause in a patient with electrolyte abnormalities. Risk factors for fluoroquinolone-induced seizures may Include seizure history, electrolyte imbalances,dose unadjusted for renal insufficiency, and concomitant treatment with agents that lower the seizure threshold.