Coronavirus Disease 2019 Treatment: A Review of Early and Emerging Options

McCreary, Erin K; Pogue, Jason M

Although this development has been encouraging, supply issues in the United States and cardiovascular toxicity concerns limit the use of chloroquine. As an alternative, hydroxychloroquine, a compound that differs from chloroquine only by a single hydroxyl group, has garnered interest. Hydroxychloroquine is perceived as having better tolerability than chloroquine, which has led to long-term usage in rheumatological disorders. Historically, very limited data were published assessing the activity of hydroxychloroquine against coronaviruses. In 2006, Biot et al [17] assessed the comparative inhibitory activity of chloroquine and hydroxychloroquine against SARS-CoV-1 in Vero cells. The authors demonstrated that chloroquine had an approximately 5-fold increased potency (EC 50 of 6.5 ± 3.2 µM) compared with that of hydroxychloroquine (EC 50 of 34 ± 5 µM).