Ivermectin, a drug once touted by conservatives as a treatment for Covid, does not significantly improve recovery time for people with mild to moderate Covid-19, according to a large clinical trial published in a peer-reviewed journal.
People who took ivermectin recovered from Covid within 12 days, while people who didn’t take the drug recovered within 13 days, according to the study published Friday in the Journal of the American Medical Association. Ivermectin is approved for the treatment of parasitic worms in humans, but is primarily used as a wormer for horses.
“In outpatients with mild to moderate COVID-19, compared with placebo, treatment with ivermectin did not significantly improve time to recovery,” wrote the team of scientists led by Duke University School of Medicine. “These findings do not support the use of ivermectin in patients with mild to moderate COVID-19,” they concluded.
Early in the pandemic, when treatment options were few and far between, ivermectin gained national attention when a few groups of conservative physicians, including Front Line COVID-19 Critical Care Alliance and America’s Frontline Doctors, began touting the drug on social media and elsewhere as a treatment for Covid. But there was little data to support these claims and a study by Dr. Pierre Kory, an intensive care physician in Wisconsin and chairman of the intensive care alliance, which claimed it was an effective treatment, was later withdrawn due to flawed data.
The latest study looked at 817 people who took ivermectin tablets for three days and compared it with 774 people who took a placebo. The participants who took ivermectin were given a daily dose based on their weight. Recovery from Covid was defined as three consecutive days without symptoms.
One person died in the ivermectin group, while not one person who received the placebo died. The number of people hospitalized in each group was the same at nine participants each.
The study was conducted at 93 sites in the US from June 2021 to May 2022, when the delta variant and then the omicron variant were dominant.
The Food and Drug Administration has not approved ivermectin for the treatment or prevention of Covid and has repeatedly warned people not to use the drug for anything other than its approved purpose.
Public interest in ivermectin peaked early in the pandemic when a lab study indicated the drug slowed the replication of the virus causing Covid in a petri dish. But several studies have now shown that ivermectin offers no meaningful benefit to patients against Covid.
A study in the New England Journal of Medicine published in May found that ivermectin did not lower the risk of hospitalization from Covid.
Ivermectin is approved in the US in liquid or paste form to treat parasites in animals. There is also a tablet version that is FDA-approved to treat parasitic worms, head lice, and some skin conditions in humans.
“There’s a lot of misinformation out there, and you may have heard that it’s okay to take large doses of ivermectin. It’s not okay,” the FDA says on its website, warning people that they can overdose.
The drug regulator also strongly warned people against taking ivermectin formulations designed for animals such as horses and cows.
“For starters, veterinary drugs are often highly concentrated because they are used for large animals such as horses and cows, which weigh much more than we do – up to a ton or more. Such high doses can be very toxic to humans.” says the FDA.