Potential for the Use of Tetrandrine in the Treatment of SARS-CoV-2 Infection
It is probable from the available evidence that oral tetrandrine could be an effective agent for the treatment of SARS-CoV-2 infection in humans.
The level of inhibition of viral replication in lung attainable with standard oral dosing of tetrandrine could be of value for the treatment, or potentially the prophylaxis (pending caveats about long-term use and toxicity) of SARS-CoV-2 infection. Prophylaxis is suggested because early administration of tetrandrine relative to infection has been shown to be more effective in vitro in the context of HCoV-OC43 [18] and this may also apply to SARS-CoV-2.
As tetrandrine is already licensed and used in China as an oral tablet at the doses cited above, it is probable that these doses are safe to be administered more widely. However, evidence of conclusive pharmacokinetic and toxicological studies, as well as clinical trials are required.
Additionally, as tetrandrine is likely to operate in a different manner to antiviral agents currently being considered for the treatment of SARS-CoV-2 infection, it might make for a suitable synergistic adjunct. The administration of tetrandrine using inhalation by aerosol also stands a possibility of being effective and would have the advantage of direct delivery to the key site of infection. However, this requires further research.