Antiepileptic Drug Adherence in Patients with Epilepsy in Saudi Arabia: A Multicentre Cross-Sectional Study

Background: Medication adherence is essential for optimal seizure control in epilepsy. However, non-adherence to antiepileptic drugs (AEDs) remains common and contributes to poor clinical outcomes. Evidence on adherence patterns and determinants in Saudi Arabia is limited. This study aimed to evaluate AED adherence and identify factors associated with adherence among patients with epilepsy in Saudi Arabia. Methods: A multicentre cross-sectional study was conducted among patients with epilepsy attending outpatient clinics across multiple regions in Saudi Arabia. Data were collected between January 2023 and June 2025. Medication adherence was assessed using the self-reported 10-item Medication Adherence Rating Scale (MARS). Adherence was categorized as low (0-5), moderate (6-7), or high (8-10). Descriptive statistics summarized participant characteristics. Logistic regression was used to identify factors associated with high adherence, reported as adjusted odds ratios (aORs) with 95% confidence intervals. All analyses were performed using Stata. Results: A total of 534 participants were included. Nearly half reported a seizure during the previous six months (46.4%). High adherence was observed in 58.2% of participants while moderate adherence was reported by 27.5%, and 14.2% had low adherence. The most common adherence barrier was forgetfulness (57.3%). Fear of medication side effects was reported by 27.9% of participants. Seizure occurrence was associated with lower adherence (aOR 0.39, 95% CI 0.26-0.59). Each additional adherence barrier reduced the odds of high adherence (aOR 0.71, 95% CI 0.63-0.80). More reported side effects were also associated with lower adherence (aOR 0.92, 95% CI 0.87-0.97). Participants from the Eastern (aOR 5.06, 95% CI 1.14-22.35) and Central regions (aOR 5.36, 95% CI 1.48-19.38) showed higher adherence than those from the Southern region. Conclusions: Medication adherence among patients with epilepsy in Saudi Arabia remains suboptimal. Modifiable barriers, particularly forgetfulness and treatment side effects, should be addressed. Patient-centred adherence interventions may improve long-term seizure control and treatment outcomes. These findings should be interpreted considering the cross-sectional study design and the use of a self-reported adherence measure.