The Goa government on Monday approved the use of anti-parasitic drug ivermectin as a preventive treatment for all adults, the state’s Health Minister Vishwajit Rane said in a Facebook post. However, the World Health Organization, the US Food and Drug Administration and even the company that produces the drug have cautioned against using it.

Rane advised doctors to start the “treatment immediately, irrespective of any symptoms or anything”. He said that while the drug does not prevent coronavirus infections, it helps in reducing the severity of the disease. He added that studies have found that the drug reduces chances of mortality among Covid-19 patients.

“In this, patients will be treated with ivermectin 12mg [miligram] for a period of 5 days,” Rane said in his post. “Expert panels from the UK [United Kingdom], Italy, Spain and Japan found a large, statistically significant reduction in mortality, time to recovery and viral clearance in Covid-19 patients treated with Ivermectin.”

The minister said that ivermectin tablets would be made available at health centres across all districts in the state.

Even as Rane cited experts’ views from various countries, various organisations have cautioned advised against the usage of the drug. WHO chief scientist Soumya Swaminathan tweeted on Tuesday that the World Health Organization had advised against using the drug except within clinical trials.

Merck, the company that produces ivermectin, had also stated that the drug has no therapeutic effect against the coronavirus. In a statement in February, the company had said that its analysis showed there was no meaningful evidence of the drug for the clinical efficacy in patients with the infection.

“We do not believe that the data available support the safety and efficacy of ivermectin beyond the doses and populations indicated in the regulatory agency-approved prescribing information,” it said.

The United States Food and Drug Administration had, in March, also advised against its use. The US drug regulator had said that ivermectin tablets were used at very specific doses for some parasitic worms and was not an anti-viral drug. It was also often used to treat or prevent parasites in animals, it said.

“Taking large doses of this drug is dangerous and can cause serious harm,” the USFDA had said, taking note of multiple reports of patients who have required medical support and been hospitalised after self-medicating with ivermectin intended for horses. “FDA has not approved ivermectin for use in treating or preventing COVID-19 in humans,” the American drug regulator said in the statement.

The drug regulator added that animal drugs were often highly concentrated because they were used to treat creatures like horses and cows, which can weigh a lot more than humans do.

“Such high doses can be highly toxic in humans,” the USFDA said, adding that an overdose of the drug can cause nausea, vomiting, diarrhea, low blood pressure, allergic reactions, dizziness, problems with balance, seizures, coma and in some cases death.