Clinical Importance of Phenytoin Monitoring to Reduce Phenytoin-Related Toxicity in Saudi Patients with Epilepsy

Background: Phenytoin toxicity can result from overdose, dosage changes, drug interac-tions, or physiological alterations. Symptoms range from nausea and confusion to severe cases involving coma and seizures, though fatalities are rare. To date, no literature has been found concerning phenytoin monitoring in Saudi epileptic patients. This study is the first to inves-tigate phenytoin monitoring for toxicity prevention, optimal dosing, and adverse effect management in Saudi epileptic patients. Methods: A two-month, randomized, open-label, prospective monitoring study was conducted in Saudi epileptic patients treated with phen-ytoin. The patients (n=40) were subdivided into two groups (monitored and unmonitored) to check the prevalence of phenytoin toxicity after two months of monitoring. Results: Most patients’ current dose was 100 mg TID: 65% and 55% in the monitored and unmonitored groups, respectively. Statistical analysis showed significant differences between current doses of the patients in the monitored (P=0.010) and unmonitored groups (P=0.018). In addition, there was a significant difference between serum levels of phenytoin regarding the monitored and unmonitored groups in the first month and second month (P=0.0246 and P=0.04), respectively. Further, there was no significant difference between the kidney functions in the first second months in the monitored group (P=0.077), while there was a substantial difference in the unmonitored group (P=0.0241). Moreover, a significant dif-ference between the monitored and unmonitored groups in the first and second months for serum creatinine (P<0.001 and P=0.032) was recorded. Conclusions: The current study reports that continuous phenytoin monitoring in Saudi epileptic patients reduces the incidence of phenytoin toxicity. Toxicity was observed in 5% of monitored patients compared to 15% of unmonitored patients. Keywords: Phenytoin, Saudi Epileptic Patients, Monitoring, Toxicity