• Hydroxychloroquine, a drug that has existed for several decades, could see a resurgence of demand, after the Indian Council of Medical Research (ICMR) recommended its use as a post-exposure prophylactic (preventive medicine) against the novel coronavirus disease.
  • Last week, US President Donald Trump had said a hydroxychloroquine-azithromycin combination could be a “game changer” in the fight against COVID-19.

What is known about hydroxychloroquine’s efficacy in COVID-19 patients?

  • Hydroxychloroquine (not to be confused with anti-malaria drug chloroquine) is an oral drug used in the treatment of autoimmune diseases such as rheumatoid arthritis. On March 19, an article in The Lancet Global Health explored its therapeutic and prophylactic properties. “Notably, the drug shows antiviral activity in vitro against coronaviruses, and specifically, SARS-CoV-2 [the virus that causes COVID-2]. Pharmacological modelling based on observed drug concentrations and in vitro drug testing suggest that prophylaxis with hydroxychloroquine at approved doses could prevent SARS-CoV-2 infection and ameliorate viral shedding.” It also mentioned clinical trials currently under way in China on whether the drug can be used for treatment.
  • In a note for physicians on the therapeutic options for COVID-19, the US Centers for Disease Control and Prevention (CDC) says: “Hydroxychloroquine is currently under investigation in clinical trials for pre-exposure or post-exposure prophylaxis of SARS-CoV-2 infection, and treatment of patients with mild, moderate, and severe COVID-19. In the United States, several clinical trials of hydroxychloroquine for prophylaxis or treatment of SARS-CoV-2 infection are planned or will be enrolling soon.”
  • The CDC says both hydroxychloroquine and chloroquine have in vitro activity against SARS-CoV, SARS-CoV-2, and other coronaviruses, with hydroxychloroquine having higher potency against SARS-CoV-2. “A study in China reported that chloroquine treatment of COVID-19 patients had clinical and virologic benefit versus a comparison group, and chloroquine was added as a recommended antiviral for treatment of COVID-19 in China…”

What has India recommended?

  • The National Taskforce for COVID-19 has recommended hydroxychloroquine for prophylaxis in case of asymptomatic healthcare workers involved in the care of suspected or confirmed cases of COVID-19 and asymptomatic household contacts of laboratory confirmed cases. The new guidelines say: “Hydroxy-chloroquine is found to be effective against coronavirus in laboratory studies and in-vivo studies. Its use in prophylaxis is derived from available evidence of benefit as treatment and supported by pre-clinical data… The following recommendation… is based on these considerations, as well as risk-benefit consideration, under exceptional circumstances that call for the protection of high-risk individuals.”
  • Doctors in the private sector are, however, cautious. “ICMR guidelines are very specific for specific people. We have to limit it to them. It cannot become something that everybody uses,” said Dr S Chatterjee, consultant at Indraprastha Apollo Hospitals.


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