It's a drug that's been supported by some conservative media figures, but taking ivermectin to treat or prevent COVID-19 might land you in the hospital, a new study warns.
Interest in the drug surged last summer as the highly contagious Delta variant took over the United States. But instead of protecting against the virus, the use of a medicine typically reserved for horses and cattle has instead prompted a spike in calls to poison control centers across the country.
In response, the U.S. Food and Drug Administration has warned against using the drug, stressing that no form of ivermectin has been approved to treat or prevent COVID-19.
"You are not a horse. You are not a cow. Seriously, y'all. Stop it," the FDA tweeted back in August.
In the latest report on ivermectin, researchers said dangerous side effects from taking ivermectin can include confusion, loss of control over body movement ("ataxia"), weakness, low blood pressure, seizures, gastrointestinal distress, dizziness, vision symptoms or rash. The side effects can be triggered by taking too much of the drug or having it interact with other medications, they noted.
"It's very easy to give yourself too much. Most people who develop symptoms probably took too much, but we did have several people who were taking it for days and weeks and then developed toxicity," said lead researcher Dr. Robert Hendrickson. He is associate medical director of the Oregon Poison Center and a professor of emergency medicine at Oregon Health and Science University, in Portland.
"It's an unusual medication in that it has a lot of interactions, so even if you're taking the normal dose prescribed for other disorders, you can get sick because of interactions with other medications," he explained. "It's usually a medication we're fairly careful with."
Hendrickson explained that ivermectin can accumulate in the brain. "That's where most of the toxicity is -- you get off balance, you get confused and feel weak -- that's where most of the interactions are," he said.
Early studies in cell cultures seemed to indicate that ivermectin could prevent COVID-19 from entering cells, but that has not panned out in humans, Hendrickson said.
Yet, the drug continues to be touted by those who oppose COVID-19 vaccines, even though no proof exists that it is effective in preventing or treating COVID-19, he said.
For the study, Hendrickson's team reviewed ivermectin-related calls to the Oregon Poison Center in August. In all, 21 people reported side effects after taking the drug.
Most of the reports came from people over 60 years of age. Eleven of the reports were from people who took ivermectin to prevent COVID-19. The other 10 took the drug to treat COVID-19 symptoms.
Among those taking ivermectin, three had a prescription from a doctor or veterinarian, and 17 purchased veterinary versions of the drug. Where the others got the drug isn't known.
For most people, adverse symptoms developed within two hours after taking a large, first-time dose of the drug. In six people, symptoms developed over several days to weeks after repeated doses taken every other day or twice weekly. One person was also taking vitamin D to treat or prevent COVID-19.
Six of the 21 were hospitalized for toxic effects from ivermectin, and all said they took the drug to prevent COVID-19, including the three who had a prescription for the drug.
Of the six hospitalized, four were treated in an intensive care unit, and none died. Among those hospitalized, gastrointestinal distress, confusion, ataxia, weakness, low blood pressure and seizures were the most common adverse side effects.
For those not hospitalized, the most common symptoms were gastrointestinal distress, dizziness, confusion, vision symptoms and rash, the researchers found.
Hendrickson noted there isn't any treatment for the side effects of ivermectin. "It's just a matter of waiting and supportive care," he said.
Since August, reports of serious side effects from ivermectin have continued, although not as many, Hendrickson said.
Dr. Robert Glatter, an emergency medicine physician at Lenox Hill Hospital in New York City, said, "Simply put, there is no clinical use for prescribing ivermectin to treat or prevent COVID-19. It's irresponsible and frankly dangerous for health care professionals to even consider prescribing ivermectin for treatment or prevention of COVID-19."
Although the drug may inhibit replication of the virus in a test tube, based on multiple studies and reviews, it does not have any true clinical value for treating people with COVID-19, he said.
"The only indication for prescribing ivermectin is to treat a parasitic intestinal infection known as strongyloidiasis [roundworm]. It also may be used for onchocerciasis [river blindness] or as a topical treatment for pediculosis [lice] and rosacea. In general, it had value treating parasites in pets and livestock," Glatter said.
The misinformation related to ivermectin has the potential to cause serious medical complications that could be deadly, he warned. "It's vital that the public consult official and trusted medical sources such as the U.S. Centers for Disease Control and Prevention or the U.S. National Institutes of Health for validated and safe approaches for treatment of COVID-19," Glatter stressed.
The report was published online Oct. 20 in the New England Journal of Medicine.
For more on ivermectin and COVID-19, head to the U.S. Food and Drug Administration.
SOURCES: Robert Hendrickson, MD, associate medical director, Oregon Poison Center, professor, emergency medicine, Oregon Health and Science University, Portland; Robert Glatter, MD, emergency medicine physician, Lenox Hill Hospital, New York City; New England Journal of Medicine, Oct. 20, 2021, online