Antidepressants and risk of postural hypotension: a self-controlled case series study

Background Antidepressants are associated with postural hypotension (PH), but it is not typically recognised as a common adverse effect. PH is linked with serious complications in older adults (e.g. falls, stroke, cognitive decline). Randomised Controlled Trials (RCTs) examining antidepressants often exclude older people and do not focus on adverse effects. Aim To examine risk of PH associated with antidepressants in adults aged ≥60 in UK primary care. Design & setting Self-controlled case series using routinely collected primary care data from the IQVIA Medical Research Database (IMRD). Method We obtained data from >41,000 adults aged ≥60 in IMRD between 1 Jan 2000 to 31 Dec 2018. Antidepressant prescriptions were determined using code lists based on British National Formulary classification. Risk of PH was examined during four risk-periods (90-days pre-prescription; day 1-28, 29-56, 57+) compared with periods outside these risk windows. Results Amongst 41,005 people with incident PH in the study period, 8,313 were prescribed a selective-serotonin reuptake inhibitor (SSRI); 8,899 were prescribed a tricyclic antidepressant (TCA); and 4,656 were prescribed an "Other antidepressant". We observed a consistent increased risk of PH in day 1-28 in all antidepressants, that reduced thereafter. Risk of PH was highest with SSRIs (IRR 4.22, 95% CI: 3.76-4.74), followed by "Other antidepressants" (IRR 2.17 (95% CI: 1.76- 2.68), TCAs (IRR 2.12, 95% CI: 1.79-2.50). Conclusion A striking increased risk of PH was observed with all antidepressants in the first month, particularly SSRIs. Prescribers should be aware of this risk and may consider PH monitoring when initiating antidepressants.