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CDC warns against using anti-parasite drug to treat or prevent COVID-19

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The Centers for Disease Control and Prevention issued a new health advisory Thursday reiterating that ivermectin does not treat or prevent COVID-19. The drug, which is commonly used to treat parasites in humans and animals, is selling out at veterinary stores and has become a common prescription request across the U.S. 

Ivermectin has been approved by the Food and Drug Administration to treat river blindness, intestinal strongyloidiasis, head lice and rosacea in humans. When used as prescribed for those conditions, it is "generally safe and well tolerated," the CDC said. But the National Institutes of Health has determined there is "insufficient data" to recommend the drug for COVID prevention and treatment, and the FDA has not approved it for such uses either. 

Back in March, the FDA published an advisory warning people: "Never use medications intended for animals on yourself. Ivermectin preparations for animals are very different from those approved for humans." 

Seven studies on the drug have published results in the U.S. National Library of Medicine, but all of them have small sample sizes, "incomplete information and significant methodological limitations," the NIH said. Several clinical trials are underway or recruiting participants to study future implementation.

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However, outpatient retail pharmacies have seen a 24-fold increase in ivermectin prescriptions compared to before the pandemic, the CDC found. From March 16, 2019, to March 13, 2020, there were an average of 3,600 ivermectin prescriptions a week. The week of August 13, there were more than 88,000 prescriptions in the U.S.

But as use of the anti-parasitic drug increases, so do reports of adverse effects, the CDC said. 

Poison control centers across the country have seen an uptick in calls reporting human exposures to ivermectin. In July, there was a five-fold increase in the number of calls the centers received about the drug compared to the number of calls pre-pandemic. The centers also saw an "increased frequency of adverse effects and emergency department/hospital visits," the CDC said. 

Many of the cases the CDC has seen include people ingesting ivermectin products that they purchased without a prescription, including formulas meant for large animals like horses and cattle. These formulas are highly concentrated and can result in an overdose, the CDC warned.

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"People who take inappropriately high doses of ivermectin above FDA-recommended dosing may experience toxic effects," the CDC said. Those effects can range from nausea and vomiting to ones that are more neurological, including hallucinations, seizures, coma and death. 

There are currently three COVID-19 vaccines authorized by the FDA: Johnson & Johnson, Pfizer and Moderna. 

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