Patterns and determinants of drug-drug interactions among community-dwelling older adults in Saudi Arabia: a cross-sectional study

Polypharmacy is increasingly common among older adults due to the high prevalence of chronic conditions, contributing to a greater risk of potential drug-drug interactions (DDIs). However, limited evidence exists on the patterns and risk factors of DDIs in community-dwelling older adults in Saudi Arabia. This study investigated the patterns, and determinants of DDIs among older outpatients.

A cross-sectional study was conducted between November 2024 and March 2025, targeting patients aged ≥60 years. Data were collected through structured face-to-face interviews. Potential DDIs were identified using Stockley's Drug Interactions database. Descriptive statistics were used to characterize DDI prevalence, severity, and drug pairs. A post hoc review assessed the likely clinical actions and management recommendations associated with the most frequent DDI pairs. Multivariate logistic regression was used to determine predictors of overall and severe DDIs.

A total of 285 potential DDIs were identified among 173 participants, with 67.2% experiencing at least one interaction. Potential DDIs classified as moderate and severe accounted for 69.1% and 23.2% of cases, respectively. Amlodipine, aspirin, and insulin were the most commonly implicated medications, while atorvastatin, perindopril, and gliclazide were frequently involved in severe interactions. Polypharmacy (≥5 medications) was significantly associated with both overall (aOR = 10.50; 95% CI: 2.02-54.64) and potential severe DDIs (aOR = 14.33; 95% CI: 3.84-53.55). Hypertension was significantly associated with an increased likelihood of overall potential DDIs (aOR = 4.81; 95% CI: 2.10-11.03) and potential severe DDIs (aOR = 6.81; 95% CI: 2.25-20.66).

Potential DDIs are common among older outpatients in Saudi Arabia, particularly among those with hypertension and higher medication burden. Although many interactions were classified as moderate or severe, most required monitoring rather than therapy modification, and their clinical relevance may vary depending on dosage and treatment context. Routine DDI screening and pharmacist-led medication review may enhance medication safety.