MANILA - "Kung hayop ka, 'di uminom ka."

Sen. Nancy Binay made this joke after several lawmakers pushed for the use of anti-parasitic drug ivermectin despite lack of data on its efficacy for COVID-19.

It echoed advice given by doctors of former president Joseph Estrada, who said ivermectin "is only for animals."

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The Food and Drug Administration has not approved ivermectin for use in treating or preventing COVID-19 in humans. The agency has so far allowed 3 hospitals to use ivermectin as investigational drug to treat patients infected with the novel coronavirus.

Binay urged the public to wait for scientific proof before taking the drug.

"If the science would say it doesn't work, why do we need to take it? 'Pag sinabi naman (If it says) it can help, it can treat, then let us go ahead and use this product," she said.

"But for us to take na wala pa siyang FDA approval or hindi pa siya (withouth FDA approval or not) prescribed ng (by) doctors, I don't think we should take it," she added.

In an advisory it issued last month, the FDA said registered oral and intravenous preparations of ivermectin in the country were veterinary products.

They were approved for use in animals for the prevention of heartworm disease and treatment of internal and external parasites in certain animal species.

Meanwhile, registered ivermectin products for human use were in topical formulations under prescription use only. This is used for the treatment of external parasites, such as head lice, and skin conditions, such as rosacea.

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The World Health Organization has warned against the use of ivermectin in patients with COVID-19, except for clinical trials, because of a lack of data demonstrating its benefits.

The UN health agency's recommendation followed the European Medicines Agency's warning against the drug. The US Food and Drug Administration has also recommended it not be used for COVID-19.

Merck, the biopharmaceutical company that makes ivermectin for humans under the brand name Stromectol, also said there was no scientific basis and no meaningful evidence of the efficacy of ivermectin for the treatment of COVID-19.

Several health experts also cautioned the public on using ivermectin, citing potential side effects on a person's liver or kidney.