The threat of Covid-19 has led people to do some crazy things, but along with the idea of injecting bleach into your body, one of the maddest things I’ve seen is people self-medicating with a drug normally used to treat parasites in horses, chickens and cattle.
Sales of ivermectin — a drug also used topically in humans against headlice (i.e. you rub it into your scalp, you don’t drink it) — have soared in the U.S. and Australia, thanks to a widespread rumour that it’s a safe and effective treatment for Covid.
These rumours were fuelled by a study from Egypt which claimed deaths of Covid patients in hospital dropped by 90 per cent when ivermectin was used. The study has since been retracted owing to ‘ethical concerns’, but that hasn’t stopped the frenzy.
In a desperate situation, with people dying in hospital from Covid, it’s reasonable enough to see if drugs such as ivermectin, or hydroxychloroquine (an anti-malaria drug also widely touted as a Covid treatment) might help
Viagra started as a treatment for angina, but then participants in a trial at Morriston Hospital in Swansea reported an unexpected side-effect: erections
The U.S. medicines regulator, the Food and Drug Administration, has warned that in large doses (the sort that vets use), the drug can be toxic — as it put it in one of its stranger warnings: ‘You are not a horse, you are not a cow. Seriously, y’all. Stop it.’
There are new trials investigating ivermectin, including Oxford University’s PRINCIPLE trial, which is looking for treatments at home, and it may turn out to be as effective as social media pundits claim, though I doubt it. In the meantime, I definitely advise against self-medicating.
There is, of course, nothing intrinsically wrong with seeing whether a drug developed for one purpose could be used for something completely different — known as ‘repurposing’. That’s how some of our most successful treatments came about.
Years ago, when I was making a TV series on the search for modern medicines, I looked at life-saving drugs that started out with a different purpose.
Chemotherapy drugs, for example, originated from the poison gas attacks of World War I. During World War II, fearing the Germans would use poison gas against Allied troops, two doctors from Yale University in the U.S. were asked to study mustard gas to find an antidote.
Instead of an antidote, what they discovered was something far more surprising: doctors who’d treated soldiers exposed to mustard gas in World War I had noted that this killed off many of their white blood cells, an important part of our immune systems.
It occurred to the Yale doctors that mustard gas might help patients with lymphoma, a cancer where the body starts to produce large numbers of abnormal white blood cells. They were right: mustard gas binds to the DNA of cancer cells, which then self-destruct.
The chemotherapy drugs that followed — and which are used today — have the same basic mechanism: they are cytotoxic, poisonous to dividing cells.
Since cancerous cells divide faster than healthy cells, they are poisoned more quickly.
A more recent example of a repurposed drug is Viagra, which started as a treatment for angina, but then participants in a trial at Morriston Hospital in Swansea reported an unexpected side-effect: erections.
So, in a desperate situation, with people dying in hospital from Covid, it’s reasonable enough to see if drugs such as ivermectin, or hydroxychloroquine (an anti-malaria drug also widely touted as a Covid treatment) might help.
But you need to run proper clinical trials, not have lots of people swallow them because of some social media post. Indeed, along with the creation of the Oxford/AstraZeneca vaccine, clinical trials that swiftly tell us whether a repurposed drug is helping or not has been one of the UK’s great scientific contributions to the current crisis.
The advantage of using a drug already licensed for something else is that it doesn’t have to go through all the safety trials, which can take years and cost huge amounts.
The RECOVERY trial is a particularly important example, something we should be proud of, for it has already saved millions of
