Does ivermectin (antiparasitic medication) exhibit antiviral properties?

From the Guidelines

Ivermectin has shown antiviral properties in laboratory settings, but its effectiveness in treating viral infections in humans remains limited and inconsistent, and it is not recommended for use outside of clinical trials. Ivermectin, primarily known as an antiparasitic medication, has demonstrated inhibitory effects against various viruses in vitro (in cell cultures), including SARS-CoV-2, as noted in the Infectious Diseases Society of America guidelines 1. The proposed mechanism involves ivermectin binding to the importin α/β1 nuclear transport proteins, which many viruses use to suppress the host's immune response.

Despite these laboratory findings, clinical evidence for ivermectin's effectiveness against viral infections in humans remains limited and inconsistent. During the COVID-19 pandemic, ivermectin received significant attention, but large, well-designed clinical trials have not demonstrated meaningful clinical benefits for COVID-19 treatment at standard doses (typically 0.2-0.4 mg/kg), as stated in the guidelines 1. Higher doses that might achieve antiviral effects in humans could potentially cause toxicity.

Some key points to consider include:

• Ivermectin has been shown to have anti-inflammatory effects in in vitro and in vivo studies, which may contribute to its potential mechanism of action in treating COVID-19 1.
• The guideline panel suggests against ivermectin for the treatment of hospitalized patients with COVID-19 and recommends against ivermectin for the treatment of outpatients with COVID-19 1.
• The certainty of evidence of treatment of ivermectin for hospitalized patients is very low, and for ambulatory persons, it is moderate due to concerns with imprecision and risk of bias 1.
• Ivermectin is well tolerated in doses typically used for the treatment of parasitic infections, but the potential for serious adverse events in hospitalized patients and ambulatory persons with COVID-19 treated with ivermectin cannot be excluded 1.

Overall, while ivermectin has shown promise in laboratory settings, its use in treating viral infections in humans is not supported by robust clinical evidence, and it is not recommended for use outside of clinical trials 1.

From the Research

Antiviral Properties of Ivermectin

• Ivermectin has been found to have antiviral effects against a range of viruses, including RNA viruses such as Zika, dengue, yellow fever, West Nile, Hendra, Newcastle, Venezuelan equine encephalitis, chikungunya, Semliki Forest, Sindbis, Avian influenza A, Porcine Reproductive and Respiratory Syndrome, Human immunodeficiency virus type 1, and severe acute respiratory syndrome coronavirus 2 2.
• The antiviral effects of ivermectin have also been observed against DNA viruses such as Equine herpes type 1, BK polyomavirus, pseudorabies, porcine circovirus 2, and bovine herpesvirus 1 2.
• Ivermectin has been shown to inhibit the replication of many viruses, including those in the Flaviviridae, Circoviridae, and Coronaviridae families, in vitro 3.
• The potential mechanism of ivermectin's antiviral effects involves the inhibition of nuclear translocation of viral proteins, facilitated by mammalian host importins, which is a necessary process for the propagation of infections 3.

Evidence from Studies

• A systematic review of experimental evidence for antiviral effects of ivermectin found that ivermectin inhibited the replication of many viruses in vitro, and that the potential for repurposing ivermectin as an antiviral agent is promising 3.
• Another study found that ivermectin exhibited antiviral effects in-vitro at very high concentrations, but noted that the drug's pharmacokinetic parameters reduce the likelihood that high concentrations of the drug can be achieved in-vivo 4.
• A review of ivermectin's multifaceted effects and potential clinical applications found that ivermectin has anti-parasitic, anti-inflammatory, anti-viral, and anticancer effects, and that it may help treat inflammatory conditions, viral infections, and cancers 5.
• A study found that ivermectin inhibits the replication of SARS-CoV-2 in vitro, with a single addition to Vero-hSLAM cells 2 h post-infection with SARS-CoV-2 able to effect a ~5000-fold reduction in viral RNA at 48 h 6.