Ivermectin Promoted Again for Cancer and Hantavirus as States Weigh Over-the-Counter Access

Ivermectin, an antiparasitic drug once touted as a COVID-19 treatment despite no evidence, is being promoted again for unproven uses including cancer and hantavirus, even as some states move to make it available without a prescription. Prescriptions for ivermectin have more than doubled among cancer patients, according to a study published in the Journal of the American Medical Association. Experts say there is no scientific evidence supporting these uses and warn of serious side effects.

The renewed cancer interest began after an actor on a popular podcast said his friends with stage four cancer took ivermectin and fenbendazole and no longer have cancer. That episode went viral with more than 13 million views on YouTube. According to the American Cancer Society, the claims are based on early studies of ivermectin’s effects on animals and on cancer cells in petri dishes. An oncologist at Kaiser Permanente said, “There is currently no high level evidence to support that it actually has any proven benefit in treating cancer in human beings.” Researchers at Cedars-Sinai Medical Center are conducting a small, early-stage clinical trial evaluating ivermectin combined with immunotherapy for metastatic triple-negative breast cancer. The National Cancer Institute also plans to study ivermectin for cancer treatment, and results are expected in a few months, its director said. Both the FDA and the American Cancer Society do not recommend ivermectin for treating cancer.

Ivermectin has also resurfaced amid a rare Andes hantavirus outbreak. Political figures and prominent COVID-era ivermectin advocates have promoted the drug as a potential treatment, with one post viewed millions of times on X. The Andes hantavirus can cause severe respiratory illness and has mortality rates in some outbreaks estimated at as high as 50 percent. “There is no meaningful clinical evidence for ivermectin against hantavirus, full stop,” said a senior scholar at the Johns Hopkins Center for Health Security. A professor of microbiology and immunology at Columbia University said, “There is zero evidence indicating that ivermectin would be a treatment for any hantavirus.” The only antiviral formally evaluated in clinical trials for hantavirus is ribavirin, and even those results showed limited benefit.

Meanwhile, state efforts to expand access to ivermectin continue. The South Carolina House passed legislation that would allow ivermectin to be sold without a prescription. In Georgia, lawmakers are considering a bill to make the drug available over the counter; a state House committee held a hearing this week but did not vote. At least four states — Tennessee, Arkansas, Idaho, and Louisiana — had enacted similar legislation as of last summer, and similar bills were proposed in at least 12 other states.

Experts warn that inappropriate use of the drug can cause harm, ranging from mild symptoms like vomiting and diarrhea to more severe effects like confusion, loss of balance, seizures, and even death. High doses can cause severe neuropathy or seizures, an oncologist said. Doctors also worry that unproven treatments give patients unrealistic expectations and can delay proven treatments. “For me, I feel the biggest downside of this is delay in getting the effective cancer treatments,” the oncologist said. A professor in the Departments of Pathology and Infectious Diseases at Emory University School of Medicine said some patients wished they had come to the hospital sooner instead of taking ivermectin. The FDA warns that improper use or high doses can cause serious side effects, including seizures and neurological complications. Experts recommend talking with a doctor and, when standard treatments are exhausted, considering clinical trials where side effects are carefully monitored.