Chloroquine / Hydroxychloroquine in Coronavirus COVID-19

Drug Basics

Generic (Trade) Names

  • Chloroquine phosphate (CQ; Aralen)
  • Hydroxychloroquine (HCQ; Plaquenil)

Current Uses

  • Treatment and prevention of malaria
  • Treatment of extraintestinal amebiasis
  • Treatment of certain inflammatory diseases (rheumatoid arthritis, systemic lupus erythematosus)

Mechanism of Action

  • Inhibits DNA and RNA polymerases and thus protein synthesis in susceptible organisms

Therapeutic Classes

  • Antimalarial
  • Antirheumatics (DMARDs)

For more drug details on sites powered by Unbound Medicine

Clinical Trials

Research Reports

Promising Findings

  • Yao X et al. reported in vitro activity of hydroxychloroquine in inhibiting the SARS-CoV-2 virus, cause of COVID-19.[1]
  • A small, non-controlled human trial showed decreased viral shedding in six COVID-19 patients when hydroxychloroquine was given with azithromycin.[2]

Cautionary Findings

  • Chloroquine showed a paradoxical effect on the immune system when administered in treating Chikungunya virus Infection.[3]
  • Despite in vitro activity in inhibiting the growth of several viruses, no acute virus infection has to date been successfully treated by Chloroquine / Hydroxychloroquine.[4]
  • An increasing number of studies have reported clinically significant QT Interval prolongation from CQ/HCQ +/- azithromycin[5], with some authors cautioning "first, do no harm."[6]

Current Scientific Opinion

Share this page

Share by email Share by Facebook Share by Twitter


  1. Yao X, Ye F, Zhang M, et al. In Vitro Antiviral Activity and Projection of Optimized Dosing Design of Hydroxychloroquine for the Treatment of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Clin Infect Dis. 2020.  [PMID:32150618]
  2. Gautret P, Lagier JC, Parola P, et al. Hydroxychloroquine and azithromycin as a treatment of COVID-19: results of an open-label non-randomized clinical trial. Int J Antimicrob Agents. 2020.  [PMID:32205204]
  3. Roques P, Thiberville SD, Dupuis-Maguiraga L, et al. Paradoxical Effect of Chloroquine Treatment in Enhancing Chikungunya Virus Infection. Viruses. 2018;10(5).  [PMID:29772762]
  4. Touret F, de Lamballerie X. Of chloroquine and COVID-19. Antiviral Res. 2020;177:104762.  [PMID:32147496]
  5. Mercuro NJ, Yen CF, Shim DJ, et al. Risk of QT Interval Prolongation Associated With Use of Hydroxychloroquine With or Without Concomitant Azithromycin Among Hospitalized Patients Testing Positive for Coronavirus Disease 2019 (COVID-19). JAMA Cardiol. 2020.  [PMID:32356863]
  6. DeJong C, Wachter RM. The Risks of Prescribing Hydroxychloroquine for Treatment of COVID-19-First, Do No Harm. JAMA Intern Med. 2020.  [PMID:32347894]
  7. Guastalegname M, Vallone A. Could chloroquine /hydroxychloroquine be harmful in Coronavirus Disease 2019 (COVID-19) treatment? Clin Infect Dis. 2020.  [PMID:32211771]
  8. Zhou D, Dai SM, Tong Q. COVID-19: a recommendation to examine the effect of hydroxychloroquine in preventing infection and progression. J Antimicrob Chemother. 2020.  [PMID:32196083]
  9. Colson P, Rolain JM, Raoult D. Chloroquine for the 2019 novel coronavirus SARS-CoV-2. Int J Antimicrob Agents. 2020;55(3):105923.  [PMID:32070753]
  10. Huang C, Wang Y, Li X, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet. 2020.  [PMID:31986264]
  11. multicenter collaboration group of Department of Science and Technology of Guangdong Province and Health Commission of Guangdong Province for chloroquine in the treatment of novel coronavirus pneumonia. [Expert consensus on chloroquine phosphate for the treatment of novel coronavirus pneumonia]. Zhonghua Jie He He Hu Xi Za Zhi. 2020;43(0):E019.  [PMID:32075365]
Last updated: May 2, 2020