Donald Trump’s championing of an anti-malarial drug to help fight coronavirus has reached new heights after he revealed that he is taking it himself.
The US president has frequently talked up hydroxychloroquine to tackle Covid-19 as the world seeks a vaccine to help stop the spread of the killer virus.
On Monday he announced that he’d been taking a pill a day after being offered a prescription by his doctor.
“I think it’s good, I’ve heard a lot of good stories,” he told reporters, despite it not being approved for fighting coronavirus outside hospitals or research settings.
His revelation has been condemned by scientists. But what do we know about it?
What is hydroxychloroquine and can it be used to treat Covid-19?
Hydroxychloroquine is prescribed for acute malaria.
It’s a derivative of chloroquine, also used to treat malaria, and can reduce inflammation, pain and swelling.
It’s also widely used to treat rheumatic diseases, including certain types of arthritis.
The British government has said that neither hydroxychloroquine or chloroquine are licensed to treat Covid-19 symptoms, or prevent infection.
No conclusions over their safety and effectiveness have been reached, meaning the drugs should not be used outside clinical trials.
Dr Stephen Griffin, associate professor in the School of Medicine, University of Leeds, said: "Hydroxychloroquine is not licensed for the treatment or prevention of Covid-19 by the FDA (US Food and Drug Administration), or any other agency.
"In fact the weight of evidence from most recent patient trials shows it to be ineffective, with the potential for adverse side effects including those affecting the heart."
Hydroxychloroquine side effects
Hydroxychloroquine can cause heart rhythm problems.
Dr Griffin has described the president’s remarks as “a staggering, irresponsible act that could very well also amount to self-harm", saying that people who follow Mr Trump’s example could “endanger themselves”.
He added that it’s prescribed and monitored carefully due to potential side effects.
When asked about Mr Trump, former Government chief scientific adviser Sir David King, said: "Every word he says should be ignored in terms of advice".
He added: "I'm sorry but this is not the pronouncement of a person who is listening to the scientists. He is making it up as he goes along."
Meanwhile Dr Ayfer Ali, assistant professor of strategy at Warwick Business School and an expert in drug repurposing, said using existing drugs could be the "only hope" of treating Covid-19 without a vaccine, but warned that still involved challenges.
"A drug may be less safe for a different disease or in sicker patients,” he said.
"For example, preliminary data from the US indicates that patients with Covid-19 who took hydroxychloroquine were more likely to die than patients who did not take the drug."
What has research about hydroxychloroquine found?
Studies in France and China have both looked at hydroxychloroquine.
However, neither study supports using hydroxychloroquine to treat patients with Covid-19 at the present time.
Last month there were 142 trials registered in various national and international databases involving chloroquine and hydroxychloroquine, alone, or in combination.
One example is aiming to use patients at Chelsea and Westminster Hospital and West Middlesex University Hospital in London, involving a a combination of hydroxychloroquine, zinc and azithromycin.
In America, the University of Minnesota is investigating whether hydroxychloroquine can prevent people catching coronavirus.
The World Health Organisation has also included chloroquine and hydroxychloroquine among drugs to be prioritised under its global Solidarity Trial - an international study bringing together various nations' efforts to test potential coronavirus treatments.
There are also concerns over the supply of chloroquine and hydroxychloroquine - which are required and proven to fight off malaria - should it also be used widely to treat coronavirus.
The European League Against Rheumatism (EULAR) has also said consideration must be given to the potential implications for people who already use the drugs for rheumatic diseases.