A Successful Rechallenge in a Patient With Oxaliplatin-Induced Tonic-Clonic Seizures Under Anticonvulsant Therapy.

Background: Oxaliplatin is an alkylating chemotherapeutic agent which is FDA-approved for colorectal cancer treatment. The most frequent neurologic complication reported with oxaliplatin is acute peripheral neuropathy. Posterior reversible encephalopathy syndrome (PRES) is another neurologic adverse effect that has been reported with oxaliplatin-based chemotherapy regimens resulting in seizures. Oxaliplatin-induced seizure in the absence of PRES is rare and has been reported in four case reports. Case Presentation: We report a case of tonic-clonic seizures after oxaliplatin administration in the absence of any other abnormal radiological or laboratory findings in a 58-year-old male diagnosed with rectal adenocarcinoma. In this case, tonic-clonic seizures occurred a few hours after oxaliplatin administration in two episodes lasting 1 min each, two and a half hours apart. The patient's vital signs, EEG, and brain MRI showed no abnormalities. The patient received levetiracetam after the seizure onset and was successfully retreated with oxaliplatin 6 months later. Conclusion: This case highlights a rare presentation of oxaliplatin-induced seizure occurring in the absence of PRES or other identifiable metabolic, structural, or infectious causes. Notably, successful rechallenge with oxaliplatin was achieved after a prolonged seizure-free interval and under antiepileptic coverage, suggesting that rechallenging may be considered in selected patients following multidisciplinary evaluation.