Purpose: The purpose of this study is to describe the pharmacotherapeutic, demographic, and socioeconomic characteristics of patients with pharmacoresistant epilepsy treated at a specialized outpatient clinic, as well as to assess the knowledge and adherence of patients to pharmacological treatment and to identify the most frequent adverse events (AE). Methods: Cross-sectional study, based on an interview using validated questionnaires and document analysis of medical records. Results:There was a high prevalence of polytherapy 92.1 % (200/217), and an average treatment time of 25.8 years. The most used antiepileptic drugs were clobazam, lamotrigine, carbamazepine and topiramate. The average AE score was 41.4 points (SD = 11.4). Regarding access to the drugs used, 66.4 % (144/217) of the patients reported having free access. The patients' knowledge about antiepileptic drug therapy obtained a mean score of 93.5 points (SD = 16.7 points), and these patients with more excellent knowledge also had greater adherence to treatment [OR= 2.51 (95 % CI, 1.11; 5.65)] and a lower incidence of AE [OR= 0.47 (95 % CI, 0.27; 0.83)]. Non-adherence rates were found to be 47.5 % (103/217), and variables that were significantly associated (p˂0.05) with non-adherence were found. Conclusion: Patients have good knowledge about pharmacological treatment, and prescriptions are in line with national guidelines, but they need integrated and continuous care work to optimize adherence and health services.