Potential Drug-Drug Interactions in Elderly Patients Treated with Anti- Glaucoma Agents: A Cross-Sectional Study in North of Iran

Background and aim: Glaucoma is one of the world's leading causes of blindness. This disease applies especially to older individuals who often require systemic drugs for other co-morbidities. In this age group, risks of polypharmacy can give rise to concerns over drug-drug interaction (DDI) that may compromise both safety and therapeutic efficacy for patients. The objective of this research is to study the DDI frequency and severity in older patients with glaucoma on systemic medications. Methods: A cross-sectional study involving glaucoma patients aged 60 years and above was conducted in Amiralmomenin Hospital, Rasht, Iran. The data regarding drugs was obtained during patient interviews and through their medical records. Potential DDIs were searched for Lexicomp and Micromedex software. Statistical analysis was also performed using SPP version 21 to determine the prevalence and severity of the interactions. Results: Among the studied 256 patients, 57%, with a mean age of 68.4 ± 4.2 years, were found to be taking at least 5 drugs. DDI was found in 75.8% of cases, while 23% of such cases involved systemic and ocular medications. Lexicomp identified significant DDI in 66.6% of cases while Micromedex found it in 75.8%, indicating sensitivity differences in detection. Most commonly involved drugs were Beta-blockers and carbonic anhydrase inhibitors, especially in combination with antihypertensive and diabetic medications. Independent risk factors for clinically significant DDIs were noted to be diabetes, heart disease, and age ≥70 years (p < 0.05). Conclusion: Many elderly patients encountered possible DDI experiences with glaucoma medications and systemic medications. Drugs for glaucoma may cause varying efficacy and safety in both topical and systemic therapies. The role of glaucoma drugs in the management of polypharmacy in the elderly is therefore important, as this can improve clinical outcomes and minimize the risk of adverse drug events.