Ivermectin: Here's what can happen with this controversial drug

Westmead Hospital in Sydney's west says it has treated a patient who overdosed after taking the drug ivermectin, an unproven and potentially dangerous treatment for Covid-19.

The person went to hospital seeking treatment for diarrhoea and vomiting side-effects, after taking the drug, which is usually used to treat parasites. The person had ordered this and other unproven Covid "cures" online.

While the patient did not die, health authorities are concerned at the number of people taking ivermectin, and warn against it for anyone else who may have Covid symptoms or has been diagnosed with the virus.

Other known ivermectin side-effects range from mild to the life-threatening, including seizures and coma.

Ever since researchers showed ivermectin could kill SARS-CoV-2 (the virus that causes Covid-19) in the laboratory, there has been interest in whether the drug would also work to kill the virus in the human body.

So far, there is no clinical evidence it works to treat or prevent Covid-19. And there is widespread consensus people should not take ivermectin at home for Covid-19.

Organisations that recommend against it include: the World Health Organization, Australia's National Covid-19 Clinical Evidence Taskforce and NPS Medicinewise, the United State's Food and Drug Administration, and the Cochrane Library.

Despite this, community pharmacists have reported increased demand for ivermectin, with people seeking the drug as a possible Covid treatment.

In Australia, ivermectin is approved to treat parasite infections in humans. It's also widely used in veterinary medicine to treat and prevent parasite infections.

However, as a prescription-only human medicine (known as schedule 4), you can only access ivermectin legally in Australia after approval from a doctor.

This is because, like all medicines, ivermectin is not 100% safe. It does have possible harmful side-effects and a doctor's judgement is necessary to decide if ivermectin is safe and appropriate for each patient.

So ivermectin is currently only recommended to treat and prevent Covid-19 when used as part of a clinical trial, where patients can be more safely selected and carefully monitored.

As well as more patients presenting to pharmacies with scripts, the Therapeutic Goods Administration warns about the danger of importing ivermectin products of unknown quality, bought over the internet.

This is risky because products may not contain the stated drug, may contain dangerous contaminants or much more of the drug than thought, which may result in an overdose.

Of most concern are reports from Australia and overseas of people buying and taking ivermectin products intended for animal use. People may be resorting to these types of products where they have been unable to access a script for human formulations of ivermectin.

We know very little about what the drug does to humans, and the little we do know mostly comes from its use in animals.

When taken at the recommended dose, the drug is generally well tolerated. But ivermectin is known to cause mild side-effects such as diarrhoea, nausea, dizziness and sleepiness. Less common, but serious, side-effects include severe skin rashes and effects on the nervous system (causing tremor, confusion and drowsiness).

In higher doses, and overdose cases, these side-effects can be more severe. These include low blood pressure, problems with balance, seizures, liver injury, and it can even induce comas.

The public is understandably interested in medicines to treat and prevent Covid-19. However, misinformation about ivermectin and others continues to circulate.

Covid-19 vaccination remains the best way to reduce the risk of serious illness and death from Covid-19. Australia's National Covid-19 Clinical Evidence Taskforce provides the most up-to-date information about Covid-19 treatments and is a reliable source of information as new knowledge emerges.

If you or a family member take ivermectin and have strong side-effects you should seek medical advice. Call the Poisons Information Centre on 131 126. For life-threatening symptoms, call 000 for an ambulance.