Antiviral Drugs

Abstract

Antiviral drugs have now been developed against infections caused by influenza, herpes, human immunodeficiency virus (HIV), hepatitis C and hepatitis B viruses. Drug resistance is a practical problem and is stimulating the wider search for new drugs using compound libraries, molecular technology and particularly X‐ray crystallography. Drug combinations are used to treat people living with HIV to reduce the opportunities for virus mutations. The threat of a global influenza pandemic has led to government stockpiling of anti‐influenza drugs. A new influenza drug inhibiting a stage of the RNA replicase has clinical activity. Epidemic HIV and hepatitis C are targeted for enhanced control by antiviral drugs during the next decade. Rapid diagnostic tests and quantitation of virus RNA or DNA are key factors to monitor for drug efficacy and resistance.

Key Concepts

  • The use of combination therapy against hepatitis B and C, HIV and influenza with more than one antiviral drug, each with a differing mode of action, to reduce the chance of emergence of drug resistance.
  • Some newer antivirals inhibit members of more than one family, for example reverse transcriptase inhibitors against hepatitis B and HIV, but a broad antiviral spectrum activity is still rare.
  • Potentially new target viruses are emerging such as SARS‐CoV, MERS‐CoV, Zika virus and Ebola. Climate change could enable mosquito‐borne Zika virus to spread more widely.
  • Influenza A remains a global threat, and pandemics can emerge from avian reservoirs of migrating geese and ducks quite rapidly. This has led to stockpiling of anti‐influenza drugs.
  • The absence of either HIV or hepatitis C vaccines continues to stimulate the search for more effective antiviral drugs.
  • Drug combinations of Directly Acting Antivirals (DAA) for hepatitis C and drugs for monotherapy to treat hepatitis B are being discovered and used in clinical practice very rapidly.
  • New public health initiatives in the United States aim to use DAA alongside rapid diagnostics and molecular quantification of virus replication to control epidemic HIV, hepatitis B and hepatitis C by the year 2030.

Keywords: antivirals; influenza; HIV; herpes; hepatitis

Figure 1. Ribbon drawing of influenza A neuraminidase (NA) enzyme. (a) Normal influenza NA and (b) oseltamivir inhibitor bound to the active site of the NA.
Figure 2. Space‐filling model of influenza A NA enzyme with zanamivir inhibitor bound at the active site.
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Oxford, John S, and Oxford, Juliette R(May 2020) Antiviral Drugs. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0000410.pub3]