A pharmacovigilance study to quantify the strength of association between the combination of antimalarial drugs and azithromycin and cardiac arrhythmias: implications for the treatment of COVID-19.

Background: Hydroxychloroquine, an antimalarial drug, combined with azithromycin has been considered a potential treatment for COVID-19. However, these drugs may cause electrocardiogram QT prolongation (QTp) and torsade de Pointes (TdP). We examined potential safety signals for these cardiac arrhythmias. Methods: Using the OpenVigil 2.1 MedDRA platform, we mined data from the U.S. Food and Drug Administration's Adverse Event Reporting System (FAERS) from December 2019 to June 2020. We extracted individual case safety reports based on exposures of seven antimalarial drugs, azithromycin, and combinations. All other drugs in FAERS served as controls. Events of interest included QTp and TdP, with associations between drug exposures and events expressed as adjusted Reporting-Odds-Ratios (aRORs) and confidence intervals. The lower end of aROR 95% confidence interval >1 was used as the statistically significant signal detection threshold. Results: QTp safety signals were found for hydroxychloroquine[aROR:11.70 (10.40-13.16)], chloroquine[aROR:18.97 (11.30-31.87)], quinine[aROR:16.66 (10.18-27.25)], atovaquone[aROR:6.91 (4.14-11.56)], azithromycin alone [aROR:28.02 (22.87-34.32)] and hydroxychloroquine + azithromycin [aROR:75.23 (51.15-110.66)]. TdP safety signals were found for hydroxychloroquine [aROR: 5.62 (4.94-6.38)], chloroquine[aROR:49.37 (30.63-79.58)], and hydroxychloroquine + azithromycin[aROR:33.09 (21.22-51.61)]. Conclusion: Hydroxychloroquine/chloroquine and/or azithromycin was associated with QTp/TdP safety signals and their use should be monitored carefully.