THERAPEUTIC DRUG MONITORING OF SERUM PHENYTOIN FOR EARLY POST TRAUMATIC SEIZURE PROPHYLAXIS IN TRAUMATIC BRAIN INJURY PATIENTS USING EMIT ASSAY IN A TERTIARY CARE HOSPITAL

Aims & Objective: To monitor therapeutic drug level of serum phenytoin for early posttraumatic seizure prophylaxis in traumatic brain injury (TBI) patients using enzyme multiplied immunoassay technique (EMIT) in a tertiary care hospital. Materials and Method: In this observational, open-label, non-interventional, prospective study, 90 patients of mild to moderate TBI patients were recruited, and serial monitoring of total serum phenytoin level along with concomitant serum albumin was done on day 3, 5, and 7 using EMIT assay. The monitoring of phenytoin drug levels along with Glasgow coma score and any episode of posttraumatic seizures was assessed. Results: The most common mode of injury was road traffic accidents (61.1%). Patients with total serum phenytoin level in sub-therapeutic level on days 3, 5, and 7 were 20%, 15.6 %, 14%, respectively. The toxic range % was 0%, 1.1%, and 7% on the three respective days. Conclusion: This observational study concludes that serial therapeutic drug monitoring (TDM) of phenytoin in TBI patients has the advantage of optimizing the drug level within the therapeutic range and thus prevent/minimize toxicity at the earliest. Emit assay is a reliable and fast method to measure the total phenytoin level with minimum turnaround time.