Stocks of the antimalarial drug chloroquine have reportedly been selling out around the world after the drug was named as a possible treatment for the coronavirus.
Early trials are under way to find out if variants of chloroquine could be useful as a Covid-19 medicine.
But health authorities around the world are warning people not to try to self-medicate without supervision from doctors.
A man died in the US after taking chloroquine days after US President Donald Trump heavily backed it as a possible coronavirus treatment.
Here’s what we know and what we don’t know.
A 68-year-old man died and his wife, 61, became critically ill after they took chloroquine phosphate in the hope that it would prevent them becoming infected with Covid-19.
The chemical is commonly prescribed to prevent malaria, although the couple took it in the form of a powder sold to clean fish tanks, rather than tablets cleared for medical use. It’s not clear how much they took.
NBC News later quoted the woman as saying she and her husband were worried about catching Covid-19 and had heard Mr Trump discussing chloroquine as a promising treatment.
With unfortunate timing, the US president said of chloroquine in a press conference last week: “The nice part is, it’s been around for a long time, so we know that if things don’t go as planned it’s not going to kill anybody.”
The woman, who has not been named, told NBC: “Trump kept saying it was basically, pretty much a cure.”
She said her advice for others would be: “Don’t believe anything the president says, and his people, because they don’t know what they’re talking about. And don’t take anything, be so careful, and call your doctor.”
The woman also said that she had heard that America’s Food and Drug Administration had not cleared the drug for use against the coronavirus, and she confirmed that she and her husband took it in the form of fish tank cleaner.
Trump boosted chloroquine
The US president has repeatedly talked up the possible use of chloroquine and a closely-related drug, hydroxychloroquine, despite caution from his medical advisers.
In a string of tweets, he wrote: “HYDROXYCHLOROQUINE & AZITHROMYCIN, taken together, have a real chance to be one of the biggest game changers in the history of medicine (…) Hopefully they will BOTH (…) be put in use IMMEDIATELY. PEOPLE ARE DYING, MOVE FAST.”
Mr Trump falsely stated in a news conference that the FDA had approved the use of chloroquine so that it would be “available almost immediately”.
The FDA quickly clarified that this was untrue, saying “There are no FDA-approved therapeutics or drugs to treat, cure or prevent Covid-19.”
The World Health Organization has not approved the use of chloroquine or hydroxychloroquine for coronavirus patients either.
It is true that some early small trials and other anecdotal evidence suggests chloroquine and its variants may show promise as a coronavirus treatment – but much more evidence is needed.
As FactCheck reported last week, a very small trial in France produced positive results, and scientists around the world are keen to study choloroquine. But we are at an early stage.
The World Health Organization recently announced that chloroquine and hydroxychloroquine would be included in a set of international trials that aim to find an effective treatment for Covid-19.
Until large-scale clinical trials are carried out, it’s impossible to know whether the drug is effective against coronavirus or whether the risks of side-effects outweigh the benefits.
Chloroquine phosphate tablets for medical use carry warnings of a long list of possible side effects.
These include allergic reactions including difficulty breathing, life-threating changes to heart rhythm, liver problems, loss of eyesight, inflammation of the lungs, convulsions and reduced numbers of blood cells. Overdose can also be fatal.
Health authorities in Nigeria said doctors were treating three cases of chloroquine poisoning and warned people not to self-medicate.
“Height of folly”
Prof Stephen Evans, Professor of Pharmacoepidemiology at the London School of Hygiene & Tropical Medicine, said chloroquine should only be taken under medical supervision.
He said: “The active ingredient in the anti-malarial drugs is chloroquine phosphate, so from a chemical point of view you are talking about the same thing.
“However, using a fish tank cleaning product which may have many other ingredients is the height of folly.
“It is possible that using a properly approved anti-malarial drug containing chloroquine might have benefits. The dose may not be the correct one and the list of side effects is extensive.
“The precautions required and the dangers of it interfering with or being affected by other medicines are also very extensive, which is why it is a drug available only in a pharmacy under the direction of a pharmacists and preferably a doctor.
“From this tragic occurrence in the US it is clear that people will do foolish things in the belief that they are helping themselves. It is vital to listen to medical advice from people who know rather than relying on statements from those without detailed medical knowledge.
“Trying to use a product intended for household use as a medicine is always risky and as seen here, can have terrible consequences.”