SINGAPORE - Despite warnings from experts, unsubstantiated beliefs that ivermectin can cure Covid-19 still hold strong.
Forums, social media and chat groups are rife with anecdotes of how ivermectin - a prescription-only drug for treating parasite infestations - has alleviated Covid-19 symptoms. Some also claim it helps to reduce post-vaccination reactions.
Health experts and even Merck, a manufacturer of ivermectin, have said there is inadequate evidence that it can cure Covid-19. However, many studies are under way.
The authorities, including the Health Sciences Authority (HSA) which issued an advisory on Tuesday (Oct 5), have also warned that the drug may be dangerous to the person taking it.
Self-medicating with ivermectin is dangerous and the drug can be prescribed only by doctors for the purposes of treating parasitic worm infections, HSA warned.
HSA was responding to reports that members of the public tried to import ivermectin or use it to treat the coronavirus.
Last Friday, Madam Wong Lee Tak was hospitalised after taking the drug on the advice of friends who said it will protect her from Covid-19. The 65-year-old remained hospitalised but in stable condition as at Wednesday noon.
In the Telegram chat group "SG Covid La Kopi", several members cast doubts that Madam Wong became ill after consuming ivermectin. They suggested that her condition was a result of the Sinopharm vaccine she had taken on Sept 23. Their messages were later deleted.
In the "Singapore Suspected Vaccine Injuries" Telegram group, a user named Alvin said ivermectin helped to relieve his headache and chest tightness after he took his Sinopharm jab.
He encouraged others to do their own research on using the drug to treat post-vaccination symptoms, citing articles published by the Front Line Covid-19 Critical Care Alliance.
The alliance, which began as a non-profit network of doctors trying to establish Covid-19 protocols in the early days of the pandemic, has come under scrutiny for its affiliation with prominent anti-vaccine organisations.
A user named Jean Nee said she read that ivermectin can overcome any Covid-19 variant. She did not state her sources.
Another user, Star Light, pointed members to a database of studies on ivermectin's use in preventing and treating the virus.
However, infectious diseases specialist Leong Hoe Nam said many of these studies were not based on consistent results and had flawed designs.
Dr Leong, who is from the Rophi Clinic at Mount Elizabeth Novena Hospital, said many of the reports he had seen promoting ivermectin as a cure for Covid-19 suggested dosages that were "much higher than the usual dose".
"There are risks to the medicine," he said, adding that he prescribes ivermectin to his patients only in single doses to treat parasite infections such as roundworms or scabies.
In large doses, the drug can become toxic, which is what Madam Wong could have experienced, Dr Leong said.
For adults, oral dosage is usually 0.15mg per kg of body weight as a single dose, with the next dose taken three to 12 months later if necessary.
Madam Wong had bought about 1,000 ivermectin tablets for $110 through an order allegedly facilitated by her friends. It is believed she took four 3mg tablets before being hospitalised on the second day of taking the drug.
Many members in three chat groups seen by The Straits Times shared websites, said to be based in India, selling ivermectin.
The drug is also in high demand in the United States, despite warnings by the US Food and Drug Administration (FDA) that it is not suitable as a Covid-19 treatment.
Prescriptions for ivermectin jumped more than 88,000 per week in mid-August, according to researchers from the Centres for Disease Control and Prevention. Before the pandemic, there were about 3,600 prescriptions weekly.
Poison control centres in Florida, Mississippi and Texas reported a recent surge in cases linked to ivermectin overdose, the National Geographic reported on Sept 3.
Ivermectin was developed in the 1970s by scientists on a mission to stop parasitic infections.
The discovery of a new species of bacteria - Streptomyces avermitilis - which could eradicate worms in mice, led to the creation of ivermectin.
It was first approved for use in animals and is often used to deworm horses in farms. In 1996, the FDA approved it for use in humans and it quickly earned its reputation as a "wonder drug".
Ivermectin was one of many drugs studied when scientists were looking to find safe generic drugs that could be repurposed for Covid-19 treatment.
One of the earliest studies in June 2020, by the National Centre for Biotechnology Information, showed that high doses of ivermectin could subdue the virus responsible for Covid-19.
This had not been shown in animals or humans, but the headline-grabbing results led many people to latch on to the hope that it was the silver bullet the world was seeking.
Those beliefs are unwavering in some circles despite warnings from the health authorities that ensued.
"The concept of a repurposed drug, a cure that was always available right under our noses, makes it so appealing," said Dr Leong.
Little was known about Covid-19 vaccines and fears of allergy made them difficult to trust at the time, he added.
He said the large chat groups encouraging the use of ivermectin make him worried and he urged their members to exercise discernment.
"The Internet is full of echo chambers and silos of various thoughts. Each person becomes more assured of his unshakeable belief, and closes (his) mind to reality or reason," he said.
HSA warned on Tuesday that it will take strong action against the illegal sale and supply of ivermectin and other medicine.
Those convicted of selling these drugs illegally can face a penalty of up to $50,000 and/or imprisonment of up to two years.