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Mayo Clinic doctor on people using horse drug ivermectin for COVID: 'It's hard to explain'

Demand for ivermectin — and calls to poison control — have surged in recent weeks.

A Mayo Clinic infectious diseases expert offered a blunt assessment when asked about people's use of an unapproved horse drug to treat COVID-19. saying in part: "It's hard to explain."

Dr. Gregory Poland, head of Mayo Clinic's Vaccine Research Group, said on a Mayo Clinic Q&A podcast Monday the number of people "flocking" to the drug, ivermectin, is "astounding." Ivermectin is approved by the Food and Drug Administration (FDA) to treat specific instances of parasitic worms in humans, as well as some skin conditions. There is also an animal-grade version used to prevent parasites.

It is not an anti-viral drug, the FDA says, and there is mixed evidence at best right now that it is effective in dampening COVID-19.

Related: Most new COVID-19 cases in MN now coming from outside 7-county metro

Yet demand for ivermectin, driven by misinformation, has skyrocketed. The Centers for Disease Control and Prevention (CDC) said last week ivermectin prescriptions have gone up 24-fold compared to before the pandemic. There had been about 3,600  prescriptions per week prior to COVID — the week ending Aug. 13 saw 88,000 prescriptions dispensed.

"If I said to you, you know what, instead of an FDA-approved vaccine that's been tested in hundreds of thousands of people. Instead, let's take a drug that's used to treat parasites," Poland said on the Mayo Clinic podcast. "And many people are buying it over the counter in an animal treatment preparation that hasn't been studied for this, which makes people sick, can cause hallucinations, coma, and if you take it when you're pregnant, can cause birth defects, and let's use that instead."

In May, the University of Minnesota Medical School began a $1.5 million clinical trial of ivermectin to treat COVID-19. The school, as of Aug. 11, said existing trials show "mixed results," noting "there is insufficient data at this time to recommend its use in COVID-19." As for trials that suggest some potential benefit, the school says these studies are not peer-reviewed and have various flaws, including a small sample size and inconsistent dosage.

Poland described these existing studies as "very poorly conducted trials," noting the Cochrane Collaboration said there's no data to suggest ivermectin is effective at treating COVID-19.

Merck, which produces ivermectin and would benefit financially from a surge in sales, even said earlier this year there is "no scientific basis for a potential therapeutic effect against COVID-19," "no meaningful evidence for clinical activity or clinical efficacy in patients with COVID-19 disease," and a "concerning lack of safety data in the majority of studies."

The CDC also noted five times as many ivermectin-related calls coming into poison control centers in July 2021 compared to before the pandemic. These calls often involve "adverse effects and emergency department/hospital visits," the CDC said.

The Minnesota Poison Control Center told Bring Me The News it received nine calls for ivermectin exposure in August.

"So, this is one of those, you can't even believe that you're seeing and hearing this," Poland said. "You can't believe the number of calls to poison control centers as people take this drug unregulated, often taking the animal preparation, which is not FDA regulated, has other ingredients in it that human forms of the drug do not have, and they're getting sick, and no benefit. 

"It's hard to explain."

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