International cohort studies suggest that adding azithromycin to hydroxychloroquine (HCQ) treatment may increase heart failure and cardiovascular mortality, potentially due to synergistic effects on QT length of ECG. Severe adverse events associated with HCQ-azithromycin were compared to HCQ-amoxicillin in rheumatoid arthritis patients aged 18+ and followed up over 30 days. A total of 323,122 and 351,956 users of HCQ-azithromycin and HCQ-amoxicillin were included. When azithromycin was added to HCQ, an increased risk of 30-day cardiovascular mortality (HR2.19), chest pain/angina (HR 1.15), and heart failure (HR 1.22) were observed. HCQ is a drug for malarial and for systemic lupus erythematosus. It recently received Emergency Use Authorization by the FDA for use to treat COVID-19 patients. Source: https://www.medrxiv.org/
