Objective: To describe phenytoin-induced rare hypersensitivity and dose related reactions, emphasizing the importance of early omission of drug to achieve clinical improvement. Design: Case series and review of literature. Setting: Tertiary level medical intensive care unit. Patients: Three cases, two of whom had hypersensitivity reactions and the third had drug-induced dyskinesia. Intervention: Omission of phenytoin and corticosteroid therapy in two cases. Results: Improvement and discharge. Conclusion: A high index of suspicion of drug-induced complications is necessary especially when multiple drugs are being administered to critically ill patients.

Patients with large variations in phenytoin levels despite standard doses may prove to become difficult clinical problems. Our study of 34 head injury patients whose serum phenytoin levels were measured on day one and day five following intravenous loading and maintenance dose of phenytoin, showed 38.24% patients, to have therapeutic phenytoin levels on day one, while 20% were in toxic range. On day five, 23% patients were in toxic and 29.41% were in therapeutic range. Only 21% patients remained in the therapeutic range during the monitoring period. This study shows that there is a wide variability of phenytoin levels in the ICU patients with a difference of more than 100% between the highest and lowest phenytoin level in individual cases (in four patients the difference exceeded 500%) raising concern about the safety of the drug. Hence it is recommended that intensive care unit patients receiving phenytoin therapy should have periodic serum phenytoin obtained even in absence of seizures or classic signs phenytoin toxicity.

An audit of 27 ventilated patients who underwent percutaneous endoscopic gastrostomy (PEG) in ICU revealed that this procedure could be safely performed in the ICU under local anesthesia. None of the patients had any hemodynamic or respiratory complications. All of them could be started on enteral feeds on the following day. PEG done in the ICU avoids the complications of transportation to the operation theater and general anesthesia.