Emetine is a potent
antiviral that acts on many viruses in the low-nM range, with several studies in animals and humans demonstrating
antiviral activity. Historically,
emetine was used to treat patients with Spanish
influenza, in the last stages of the pandemic in the early 1900s. Some of these patients were "black" with
cyanosis.
Emetine rapidly reversed the
cyanosis and other symptoms of this disease in 12-24 h. However,
emetine also has been shown to have anti-inflammatory properties and it appears it is these anti-inflammatory properties that were responsible for the effects seen in patients with Spanish
influenza.
Emetine, in the past, has also been used in 10s to 100s of millions of people at a dose of ~60 mg daily to treat
amoebiasis. Based on viral inhibition data we can calculate a likely SARS-CoV2
antiviral dose of ~1/10th the
amoebiasis dose, which should dramatically reduce the risk of any side effects. While there are no anti-inflammatory dose response data available, based on the potential mode of action, the anti-inflammatory actions may also occur at low doses. This paper also examines the toxicity of
emetine seen in clinical practice and that seen in the laboratory, and discusses the methods of administration aimed at reducing side effects if higher doses were found to be necessary. While
emetine is a "pure
drug" as it is extracted from
ipecac, some of the differences between
emetine and
ipecac are also discussed.