Researchers are investigating the potential of the broad spectrum anti-microbial ivermectin for COVID-19 treatment.

As the COVID-19 pandemic, caused by the SARS-CoV-2 virus, continues to spread around the world, researchers are looking for candidate drugs to use as potential therapies. Repurposing drugs already in use for other infections could allow a quicker route to finding safe and effective COVID-19 treatments. One example being investigated is ivermectin for COVID-19 treatment.

Anti-microbial drugs already in use may be potential COVID-19 treatments

Ivermectin is an antimicrobial drug with a wide range of actions including anti-parasite, anti-viral, anti-bacterial and anti-cancer properties. It has been used in veterinarian medicine as an anti-parasitic treatment since the early 1980s and is also used to treat several diseases in humans, including the parasitic tropical disease onchocerciasis (river blindness). Ivermectin has also been shown to have potent antiviral actions against several viruses that infect humans, although many of these effects have been seen in the laboratory rather than in clinical trials. Researchers in Australia tested the antiviral effects of ivermectin on the SARS-CoV-2 in the laboratory to assess the potential of ivermectin for COVID-19 treatment. They recently reported their results in Antiviral Research.

Ivermectin eradicated the SARS-CoV-2 virus from cell cultures

The researchers infected cell cultures in the laboratory with the SARS-CoV-2 virus. Two hours later, some of the cell cultures were treated with ivermectin and others were left untreated. By 48 hours, the SARS-CoV-2 virus had been eradicated in the ivermectin-treated cell cultures.

“We found that even a single dose could essentially remove all viral RNA by 48 hours and that even at 24 hours there was a really significant reduction in it,” said Dr. Kylie Wagstaff, from the Monash Biomedicine Discovery Unit, one of the lead authors of the study.

The mechanism of action of ivermectin on SARS-CoV-2 virus is unclear. Based on previous studies of ivermectin’s effects on other viruses, the drug may prevent the SARS-CoV-2 virus from “dampening down” the host cell’s viral-clearing pathways.

Clinical trials needed to test efficacy and safety of ivermectin for COVID-19

The researchers are encouraged by these initial findings. However, they caution that pre-clinical and clinical trials in humans are needed before any recommendations can be made about the use of ivermectin for COVID-19 treatment. Although ivermectin is seen as a safe drug, the concentration used in the laboratory experiments was many times higher than that seen with usual approved doses. At higher doses there may be increased risk of drug side effects.  “We need to figure out now whether the dosage you can use it at in humans will be effective – that’s the next step,” said Dr. Wagstaff.

References

1. Caly L, Druce JD, Catton MG, Jans DA, Wagstaff KM. The FDA-approved drug ivermectin inhibits the replication of SARS-CoV-2 in vitro. Antiviral Res. 2020;178:104787. doi:10.1016/j.antiviral.2020.104787

2. Monash University, Press release 3 Apr 2020. Possible coronavirus drug identified by Australian scientists. https://www.eurekalert.org/pub_releases/2020-04/mu-pcd040320.php

3. Sharun K, Dhama K, Patel SK, et al. Ivermectin, a new candidate therapeutic against SARS-CoV-2/COVID-19. Ann Clin Microbiol Antimicrob. 2020;19(1):23. Published 2020 May 30. doi:10.1186/s12941-020-00368-w

4. Heidary F, Gharebaghi R. Ivermectin: a systematic review from antiviral effects to COVID-19 complementary regimen. J Antibiot (Tokyo). 2020;73(9):593-602. doi:10.1038/s41429-020-0336-z

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