Ivermectin, a wonder drug that treats sight- and life-threatening parasitic infections, has been around for over 30 years. Its impact on global health is so significant that Nobel Prize-winning researchers who were involved in its development and discovery won it the Nobel Prize in 2015.
ISSOUF SANOGO/AFP via Getty Images – The Conversation
Since 1995, I have been an infectious disease pharmacist. I have also treated patients with severe COVID-19 infections who waited to get proper treatment because they believed ivermectin would cure them.
Ivermectin is a great treatment for certain diseases but it won't save COVID-19 patients. It could even endanger their lives.
Let me tell you about the history and development of ivermectin.
Ivermectin development for animal use
Ivermectin first became known in 1970s through a Merck Pharmaceuticals veterinary drug screening program. Researchers sought to discover chemicals that could be used to treat parasitic infections in animals. Common parasites include arthropods such as fleas or lice, as well as nematodes such as roundworms and flatworms. These infectious organisms are very different from viruses.
Merck collaborated with the Kitasato Institute in Japan, a medical research center. Satoshi Omura's team isolated a number of chemicals from bacteria that was found in one soil sample located near a Japanese course. Avermectin has not been found in any other soil sample anywhere in the world, according to my knowledge.
For approximately five years, research on avermectin was ongoing. Merck and the Kitasato Institute soon developed an easier to use form of avermectin. It was approved for commercial use in 1981 by the Kitasato Institute for parasitic infections in domestic animals and livestock. The brand name Ivomec was used.
First discovered by bacteria in the soil of a Japanese course, ivermectin's chemical compounds were found in bacteria. Pak Sang Lee/flickr, CC BY-NC
Ivermectin development for human use
Merck's William Campbell and his team discovered early that the drug could also be used to combat a human parasite, which causes river blindness.
Onchocerciasis is also known as river blindness. It is the second most common cause of blindness preventable. It is transmitted by blackflies that carry the parasitic worm Onchocerca veris to humans and it occurs mainly in Africa.
Ivermectin was tested to cure river blindness in 1982. It was finally approved in 1987. Since then, it has been freely distributed to many countries through the Mectizan Donation Program. Ivermectin has helped to eliminate river blindness in 11 Latin American countries. This prevents approximately 600,000.
Two decades of intensive work to develop, discover and distribute ivermectin significantly reduced river blindness. These efforts were the reason why Satoshi Omura and William Campbell received the 2015 Nobel Prize in Physiology or Medicine for their pioneering research.
William Campbell and Satoshi Omura were awarded the 2015 Nobel Prize in Physiology or Medicine. They were recognized for their work on ivermectin. Bengt Nyman/Wikimedia Commons
Repurposing drugs to other uses
Researchers in infectious diseases often try to repurpose antimicrobials or other medications to treat their patients. Because almost all the basic research is done, drug repurposing can be faster and more cost-effective.
Ivermectin has been proven to be effective against parasitic infections in the years that it was approved for river blindness treatment. Strongyloidiasis is an intestinal roundworm infection that can affect between 30 and 100 million people around the world.
Amphotericin B is another example, which was originally approved for treating yeast and mold infections. Researchers found that it could also be used to treat severe forms of leishmaniasis (a parasitic disease prevalent in subtropical and tropical countries).
Doxycycline, an antibiotic that is used to treat a variety of human bacterial diseases such as Lyme disease and pneumonia, can also be used. Later, it was found to be extremely effective in treating and preventing malaria.
Strongyloidiasis is an intestinal infection that can prove fatal for immunocompromised patients. Ivermectin was used to treat it. jarun011/iStock via Getty Images Plus
Repurposing drugs to COVID-19
However, not every attempt to repurpose a drug is successful.
Scientists and doctors searched for inexpensive drugs to reuse in the fight against COVID-19 at the beginning of the pandemic. Two of these drugs were chloroquine (and hydroxychloroquine). These drugs were selected because they had been shown to have antiviral properties in laboratory studies, and there are limited reports of cases from COVID-19-related outbreaks in China. These drugs were not shown to have any significant benefits in large clinical trials. This was due in part to the toxic effects that patients experienced before they were able to take high enough doses of the drug to kill or inhibit the virus.
These failed attempts were not learned and have not been used to improve ivermectin. An April 2020 Australian laboratory study revealed that ivermectin could be used to treat COVID-19. Even though the study's results were widely shared, I was skeptical. They found that the concentrations of ivermectin tested were 20 to 2,000 times greater than those used for human parasitic infections. Within a month of publication, other pharmaceutical experts confirmed my concerns. This drug can be extremely toxic at high doses.
Scientists discovered serious flaws in a paper titled 'Ivermectins and COVID-19: A Commonly cited Paper'. It was pulled from the internet on July 20, 2021. These flaws included incorrect statistical analyses, discrepancies between published data and collected data, duplicate patient records, and inclusion of subjects who had died before the study began. Two other studies, which are often cited frequently, raise serious concerns about scientific fraud.
Two large, randomised clinical trials that evaluated the effectiveness of ivermectin in COVID-19 prevention and treatment were completed at the time this article was written. Reputable international and national health care organizations including the World Health Organization and the Centers for Disease Control and Prevention strongly recommend against the use of Ivermectin to treat or prevent COVID-19.
Consequences for COVID-19: Using ivermectin
Many organizations with questionable motives have promoted the unsubstantiated use invermectin COVID-19. This has resulted in an increase in prescriptions for ivermectin and a surge of calls to U.S. poison prevention centers regarding ivermectin-related overdoses. Ingestion of large quantities of veterinary products containing Ivermectin was a major reason for many calls. Two deaths were linked to ivermectin poisoning in September 2021.
When used correctly, Ivermectin has prevented millions from potentially fatal and debilitating infections. It is only prescribed to treat parasitic infections. It is not intended to be prescribed to parasites who are trying to make money off desperate people in a pandemic. I hope this tragic and unfortunate chapter in the amazing story of a lifesaving medicine will be over soon.
This article has been updated to reflect that Ivomec is the brand name of veterinary ivermectin.
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This article was republished by The Conversation, a non-profit news site that shares ideas from academic experts. It was written by Jeffrey R. Aeschlimann from the University of Connecticut.
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Jeffrey R. Aeschlimann was awarded funding by the NIH to support collaborative research projects that focus on bacterial anti-biotic resistance.
