(088) Antidepressants and Risk of Orthostatic Hypotension: a Self-Controlled Case Series Study

Background: Orthostatic hypotension (OH) is a common adverse effect of drugs and associated with serious adverse outcomes in older people including an falls, myocardial infarction, stroke and dementia. Antidepressants have been associated with OH in trials (excluding older people) and cross-sectional studies.

Objectives: To examine the risk of incident OH associated with initiation and continuation of antidepressant treatment in adults aged ≥60 in UK primary care

Methods: Self-controlled case series study using routinely collected primary care data from the IQVIA Medical Research Database (IMRD). Patient level data were obtained from over 21,000 older adults in UK primary care between 1 January 2000 to 31 December 2018. In 41,005 older people with a first recorded diagnosis of OH during the observation period, 8,313 were prescribed an selective serotonin reuptake inhibitor (SSRI) ; 8,899 were prescribed a tricyclic antidepressant (TCA); and 4,656 were prescribed an Other antidepressant (as per British National Formulary sub-chapter categories). The risk of incident OH was examined during four risk periods (90-days pre-prescription and day 1-28, 29-56, 57+ post-prescription) vs baseline.

Results: We found an increased risk of OH within the first 28 days of all antidepressant exposure. Overall, the risk of PH was highest with SSRIs (IRR 4.03, 95% CI: 3.38-4.80), followed by TCAs (IRR 2.22, 95% CI: 1.74-2.84) then “Other antidepressants” (IRR 1.69 (95% CI: 1.32- 2.15). The risk of adverse OH reduced from day 28 onwards for all groups. Additionally, an increased risk of OH in the 90-day pre-exposure period was found for SSRIs and “Other antidepressants”, that was not observed with TCAs.

Conclusions: A substantially increased risk of OH was observed with all antidepressants in the short time period (days 1-28) after first prescription, particularly SSRIs. Prescribers should inform patients of this risk and potential symptoms to report, and consider brief advice and/or monitoring to reduce the risk of OH and its numerous adverse complications in older people.