Additional safety consideration for azithromycin in the management of SARS-CoV-2 infection

David Juurlink’s timely and otherwise thorough review of chloroquine, hydroxychloroquine and azithromycin¹ omitted an important safety consideration for azithromycin that is relevant to recipients of allogeneic blood and marrow transplantation, in whom azithromycin may be prescribed to prevent or treat transplant-related lung disease (especially bronchiolitis obliterans). In a 2017 randomized controlled trial involving participants receiving blood and marrow transplants, those assigned to receive prophylactic azithromycin had significantly higher relapse rates for their underlying hematologic malignant disease, as well as an increase in overall mortality.²

In 2018, this serious safety concern led Health Canada to warn prescribers and patients about the use of azithromycin in recipients of blood and marrow transplants. ³ Because these recipients are often profoundly immune suppressed, infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may be more common and severe. Prescribers should thus be cognizant of this potentially serious adverse effect of azithromycin in this particular group of patients.