Risk of Fractures With Concomitant Use of Calcium Channel Blockers and Selective Serotonin Reuptake Inhibitors

Abstract

Background: Despite their frequent concurrent use, little is known about the concomitant use of calcium channel blockers (CCBs) and selective serotonin reuptake inhibitors (SSRIs) on fracture risk. We compared risk of fractures in patients concomitantly treated with CCBs and SSRIs versus CCB-only users. We compared risk of fractures among concomitant CCB-SSRI users initiating cytochrome P450 3A4 (CYP3A4)-inhibiting SSRIs versus non-CYP3A4 inhibiting SSRIs.

Methods: This retrospective cohort study used IBM MarketScan commercial claims and Medicare Supplemental database (2007-2019). We included adults diagnosed with hypertension and depression, newly initiating SSRIs while being treated with CCBs (ie, concomitant CCB-SSRI users) and those who did not (ie, CCB-only users). Primary outcome was the first occurrence of any fracture. We used stabilized inverse probability of treatment weighting (sIPTW) based on propensity scores to balance baseline risk between groups. Cox proportional hazard regression modeling was used to compare fracture risk.

Results: We identified 191 352 concomitant CCB-SSRI and 956 760 CCB-only users (mean age = 56 years, 50.1% males). After sIPTW, compared with CCB-only users, CCBs-SSRIs users had a higher risk of fractures (hazard ratio [HR]: 1.43, 95% confidence interval [CI]: 1.22-1.66). No difference in the risk of fractures between concomitant users of CCB-CYP3A4-inhibiting SSRIs and those of CCB-non-CYP3A4 inhibiting SSRIs (HR: 1.10, 95% CI: 0.87-1.40) was observed.

Conclusion and relevance: Short-term concomitant CCB-SSRI use was associated with increased fracture risk. Concomitant CCBs and CYP3A4-inhibiting SSRIs compared with CCBs and non-CYP3A4 inhibiting SSRIs use was not associated with increased risk.

Keywords: calcium channel blockers; concomitancy; concurrent use; fractures; medication safety; selective serotonin reuptake inhibitors.