The association between antidepressant use and orthostatic hypotension in older people: a matched cohort study

Orthostatic hypotension (OH) is often reported as a significant potential adverse effect of antidepressant use but the association between phasic blood pressure (BP) and antidepressants has not yet been investigated. This cross-sectional study compares continuously measured phasic BP and prevalence of OH in a cohort of antidepressant users ≥50 years compared with an age- and sex-matched cohort not taking antidepressants. OH was defined as a drop in systolic BP ≥ 20 mm Hg or in diastolic BP ≥ 10 mm Hg at 30 seconds after standing, measured using continuous beat-to-beat finometry. Multilevel time × group interactions revealed significantly greater systolic and diastolic BP drop in antidepressant users than nonusers at 30 seconds after stand. The prevalence of OH among antidepressant users was 31% (63/206), compared with 17% in nonusers (X² = 9.7; P = .002). Unadjusted logistic regression models demonstrated that selective serotonin reuptake inhibitor use was associated with OH at an odds ratio of 2.11 (95% confidence interval: 1.25-3.57); P = .005, and this association was not attenuated when covariates including cardiac disease and depressive symptom burden were added. There was no statistically significant association between serotonin noradrenaline reuptake inhibitor or tricyclic antidepressant use and OH in unadjusted models although the study was not powered to detect changes within these subgroups. Older people taking antidepressants have a two-fold higher prevalence of OH than nonusers, highlighting the importance of screening the older antidepressant user for OH and dizziness and rationalizing medications to reduce the risk of falls within this vulnerable cohort.