What is an example of an antiviral drug?
Viruses are an extracellular form of life, which is a complex combination of protein structures, which in order to survive and multiply, must be embedded in the cell of the infected organism. An infected cell, instead of performing its “functional duties”, begins to synthesize the virus proteins, which as a result form new viral bodies. The host cell perishes and collapses, and newly created “aggressors” are being introduced into neighboring cells.
Today there are more than 500 types of viruses that cause human diseases. And each of them has a lot of subspecies – serotypes.
The immune system is able to recognize infected cells, that is why many antiviral medications are aimed at immunity stimulation. They are called immunostimulants (or immunomodulators). Drugs acting directly on the structure of the virus and its replication (reproduction) appeared relatively recently – after the biochemical mechanisms of the “vital activity” of the virus were discovered. These agents are called direct-acting antivirals (DAA). In general, the creation of an effective antiviral agent is not a trivial task, as the viruses parasitize inside cells.
Today, clinical pharmacological classification is the most requently used, meaning that the division of drugs into groups is made depending on types of viruses which they affect. Each highly specialized group of agents usually contains the classification of antiviral drugs, which is based on the mechanisms of their action.
Anti-influenza drugs (anti-serotypes Influenza A1, A2, B): M-2 inhibitors (blockers). The M2 protein locates in the lipid membrane of the virus and creates an ion channel during release of the virus structures from the envelope and incorporation into the cell systems. Inhibitors of this protein prevent release of the viral genome in cells. The most famous and “oldest” medications with such properties are amantadine and rimantadine. Recent studies have shown that most strains of influenza A virus have become resistant to this group of agents, so they are no longer recommended.
Inhibitors of neuraminidase. The neuraminidase enzyme helps the virus to penetrate through protective mucus of the respiratory passages towards the cells of the mucous membranes. Direct-acting antivirals (DAA), which prevent activity of neuraminidase of influenza viruses of serotypes “A” and “B” are oseltamivir and zanamivir.
Interferon agents – these are proteins that prevent the reproduction of viruses and in parallel stimulate the activity of the immune system. Recombinant human interferon alpha-2b is the first treatment aid, which is applied against influenza.
Interferon inductors (have wide range of action) are drugs stimulating the production of own interferon.