Epilepsy is among the most prevalent serious neurological disorders, affecting over 70 million people worldwide, in Algeria, the prevalence of epilepsy was estimated to be eight times more common. Carbamazepine is frequently the first-line treatment, making early prediction of patient response essential for personalized care. This approach helps reduce adverse effects and healthcare costs, while enhancing patient outcomes. This study aims to explore the link between the ABCB1 c.3435C >
T genetic variation and Carbamazepine resistance and toxicity in Algerian patients with epilepsy, with a focus on the impact of genetic variations on Carbamazepine plasma concentrations and treatment outcomes. Ninety-eight Algerian patients with epilepsy were recruited and categorized as either drug-responsive or drug-resistant based on their clinical response to CBZ treatment. Genotyping of the ABCB1 c.3435 C >
T polymorphism was performed using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method, and CBZ plasma levels were measured to assess its effect on metabolism. Clinical data, including drug response, therapy type, and adverse drug reactions (ADRs), were collected and analyzed. For the statistical analysis we used chi-squared tests and Exact Fisher's for corrections. Our findings show no significant association between the ABCB1 c.3435C >
T genotypes with carbamazepine resistance (p = 0,1) nor incidence of adverse reactions. This polymorphism also indicated no statistically significant link with Carbamazepine plasma levels. The sample size in this study might be limitation
therefore, expanded investigations on Algerian population are needed. Although this study indicates no significant correlation of the ABCB1 c.3435C >
T polymorphism with influencing CBZ Pharmacoresistance and therapeutic outcomes, larger-scale-studies are required to confirm these results and assess their reliability.