Phenytoin toxicity presenting with acute visual loss and acute delirium, a case report

Author: Sin-Hong Chew ¹ ; Irene Looi ² ; Yoke-Lin Lo ³ ; Kheng-Seang Lim ⁴
Author Information

1. Department of Internal Medicine
2. Department of Internal Medicine, 2 Clinical Research Centre, Hospital Seberang Jaya, Penang
3. Department of Pharmacy Practice, School of Pharmacy, International Medical University, Kuala Lumpur
4. Division of Neurology, Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
Publication Type:Journal Article
Keywords: Phenytoin toxicity; visual loss; epilepsy; pharmacokinetics; side effects; adverse drug event; AED; antiepileptic drug
From:Neurology Asia 2018;23(4):363-365
CountryMalaysia
Language:English
Abstract: Phenytoin is a widely prescribed antiepileptic agent for both focal and generalized seizure. We report a case of a 20-year-old man with focal epilepsy presented with acute bilateral visual loss, and delirium. His random phenytoin serum concentration on admission was 43.6 mg/L, well above the recommended therapeutic range of 10-20 mg/L. Extensive investigations have ruled out other vascular or demyelinating causes. His visual symptoms completely resolved after discontinuing phenytoin for 84 hours. This case shows that acute phenytoin toxicity can result in reversible visual failure.
Full text:7.2018.my026.pdf