This week, Trump said he has been taking hydroxychloroquine as a preventative medicine, despite a lack of scientific evidence.
In fact, hydroxychloroquine, as well as a related medicine, chloroquine, may even raise the risk for death and serious heart rhythm disorders in people who use it, an worldwide team of researchers reported. He said he was taking the drug with the approval of the White House physician.
"An association of increased overall mortality was identified in patients treated with hydroxychloroquine alone", the researchers wrote.
Bhan and others said it was inappropriate for a national health research agency to make recommendations on the basis of weak evidence.In their study, the U.S. researchers analysed data from almost 15,000 Covid-19 patients who were receiving any of four drug regimens and 81,000 controls in hospitals between December 20 previous year and April 14.
Hydroxychloroquine is safe for malaria, and conditions like lupus or arthritis, but no clinical trials have recommended the use of hydroxychloroquine for coronavirus.
It includes chloroquine and hydroxychloroquine, the same drug which U.S. President Donald Trump says he is taking.
The death rate in the control group, which did not receive either hydroxychloroquine or chloroquine, was 9.3%, the Boston team reported.
The researchers said that after considering multiple confounding factors when compared with mortality in the control group, hydroxychloroquine, hydroxychloroquine with macrolide, chloroquine, and chloroquine with a macrolide were "independently associated with an increased risk of de-novo ventricular arrhythmia during hospitalization".
As well, serious heart rhythm problems were more common in patients who received either of the four treatment regimens, Mehra's group added.
"The indications are that these drugs certainly ought not to be used outside of a trial setting where patients can be monitored for complications", said Griffin, who was not involved in the study.
Authors of a separate study that supported the use of antimalaria drugs with antibiotics for COVID requested that their paper be withdrawn, according to the Retraction Watch website.
Doctors have cautioned that the drug carries the risk of serious side-effects on the heart's functions.
Prior studies have concluded much the same.
Seriously ill COVID-19 patients who were treated with hydroxychloroquine or the closely-related drug chloroquine were more likely to die or develop risky arrhythmia, namely irregular heart rhythms that can lead to sudden cardiac death, it concluded.
Less than three hours before the ICMR issued its Friday advisory, USA researchers released a large study's findings that link hydroxychloroquine to increased rates of death and cardiac rhythm disorders among Covid-19 patients.
The FDA also warned that "hydroxychloroquine and chloroquine can cause abnormal heart rhythms".
The analysis included data from 671 hospitals across six continents, which pooled together resulted in 96,032 patients who had tested positive for COVID-19 and were hospitalized between December 2019 and April 2020. Those who received hydroxychloroquine fared no better than those who did not.
The study said there were no benefits to treating patients with the anti-malarial drug hydroxychloroquine.