Seizures associated with fluoroquinolones

Ann Pharmacother. 2001 Oct;35(10):1194-8. doi: 10.1345/aph.10359.


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

Case summary: 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.

Discussion: 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.

Conclusions: 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.

Publication types

  • Case Reports
  • Review

MeSH terms

  • Aged
  • Anti-Infective Agents / adverse effects*
  • Ciprofloxacin / adverse effects*
  • Female
  • Humans
  • Levofloxacin*
  • Magnesium / blood
  • Ofloxacin / adverse effects*
  • Seizures / chemically induced*
  • Sodium / blood


  • Anti-Infective Agents
  • Ciprofloxacin
  • Levofloxacin
  • Sodium
  • Ofloxacin
  • Magnesium