UPDATE 23 April 2020
Studies released this week in the USA and France have shown that hydroxyochloroquine is not an effective treatment for COVID-19. Of even greater concern in the US study was that the death rate amongst those receiving the drug was higher than those not taking it.
In the US study of 368 patients, 97 patients who took hydroxychloroquine had a 27.8% death rate. The 158 patients who did not take the drug had an 11.4% death rate.(1)
In the French study of 181 patients, 84 had taken hydroxychloroquine. The death rates between the two groups were the same. The drug caused serious heart rhythm problems in eight patients taking the drug and had to be stopped. (2)
UPDATE 7 April 2020
Fuelled by repeated claims that chloroquine and its sister drug hydroxychloroquine are effective treatments for COVID-19, doctors in the USA are prescribing it despite the fact there is no evidence that it works.
At a time of misinformation this article by Reuters is one I would recommend. It is well researched and factually correct.
The claims that it has successfully cured some patients are dubious. One scientist based in France making this claim has a history of publishing fraudulent research. More here:
Chloroquine and hydroxychloroquine are being studied alongside other drugs in a worldwide research trial in which the UK is taking a prominent role.
Nobody should be taking chloroquine or hydroxychloroquine as a potential COVID-19 treatment unless they are a participant in these trials.
25 March 2020
Claims by Donald Trump that the anti-malarial drugs chloroquine and hydroxychloroquine are effective in treating COVID-19 has led to their stockpiling both by individuals and some countries. A US man died after he and his wife took a non-pharmaceutical version intended for cleaning fish tanks.
Doctors are reporting seeing patients who have over-dosed on the drugs in the mistaken belief that they would protect them from COVID-19.
Chloroquine was first looked at by researchers during the 2002-03 outbreak of SARS, an illness also caused by a coronavirus.
The World Health Organisation has launched a global trial investigating several drugs, including chloroquine, that could be used to treat COVID-19 but at the time of writing there is no scientific evidence that chloroquine is effective.
Even if proven to have an effect it would be to treat established COVID-19, not to protect against infection in the first place.
Both chloroquine and hydroxychloroquine are used for other serious conditions, including rheumatoid arthritis and other autoimmune diseases, and some sufferers are now unable to access their regular prescribed drugs because of unnecessary hoarding by others.
To date these drugs have not helped in any previous viral diseases as the doses needed to kill a virus have been much higher than those needed to treat malaria and other conditions and would prove toxic to humans.
As Professor Susanne Herold, a lung disease expert from the University of Giessen in Germany recently told Science magazine “Researchers have tried this drug on virus after virus, and it never works out in humans. The dose needed is just too high.”
The FDA (Food and Drug Administration) have released a statement refuting Trump's announcement that they had approved the drugs and were making them immediately available confirming that "there are no FDA-approved therapeutics or drugs to treat, cure or prevent Covid-19."
