Background Antihypertensive medications are commonly used for a wide range of indications, yet it is unknown to what extent older adults are at risk of adverse drug reactions (ADRs) associated with their antihypertensive medication use. Objective The aim of this study was to determine the prevalence and characteristics of antihypertensive-related ADRs on hospital admission. Setting Metropolitan teaching hospital in Sydney, Australia. Method A retrospective cross-sectional audit of 503 older patients (≥ 65 years) admitted to hospital was conducted. Potential ADRS were identified from the medical record. Two independent clinical pharmacists reviewed each potential ADR using validated tools for causality, severity, preventability and contribution to hospitalization. Characteristics associated with an increased ADR risk among antihypertensive users were identified via logistic regression. Main outcome measure Antihypertensive related ADRs. Results Antihypertensives were used on admission by 68% of the cohort and the prevalence of 'definite/probable' antihypertensive-related ADRs among antihypertensive users was 16.4%. Antihypertensive medications were associated with a threefold ADR risk (OR = 3.09, 95% CI 1.85-5.16). Angiotensin II Receptor Blockers (ARB), impaired renal function, recent medication changes and previous history of allergy or ADR were all associated with an increased risk of experiencing an ADR. Conclusions ADRS associated with antihypertensive medicines were relatively common among older adults admitted to hospital. Increased awareness of those older persons who are most at risk of experiencing an antihypertensive-related ADR in the clinical setting may lead to early detection and minimization of ADR associated harms.
Keywords: Acute care; Adverse reaction; Antihypertensive medication; Australia; Drug utilization; Medication safety; Older adult.