Viruses are single cell organisms that infect human or animal cells by binding to their outer surface, getting inside and then using the cell to replicate themselves. Antiviral medications work by targeting the attachment and entry into the human cell, preventing replication of the virus and disease in the host body.
Antiviral Drugs Such as Tamiflu Treat Viral Infection
Antiviral drugs such as Tamiflu and Relenza are currently in the news due to the anticipated swine flu epidemic. These drugs cannot cure or prevent infection in the first place, but they can treat swine flu and help you recover if they are taken within 48 hours of the onset of symptoms. Antiviral treatments help relieve some symptoms of the flu and reduce the length of time it will take to recover by about a day. They also reduce the risk of serious complications from the flu such as pneumonia and make it less likely that you will infect someone else. Medical studies report that antiviral drugs are effective and safe for children over the age of one year.
There are many other antiviral medications for other viral diseases such as herpes simplex, varicella-zoster or chicken pox, cytomegalovirus, hepatitis B, hepatitis C and HIV.
Antiviral Drugs Work By Varying Mechanisms
Antiviral drugs that inhibit the replication of the type A influenza virus such as H1N1 by blocking the viral M2 protein ion channel which is needed for the virus to multiply.
Other antiviral drugs work by inhibiting viral transcription which is needed to duplicate the viral genes. These work by terminating the DNA chain. Antiviral medications such as acyclovir function in infected cells so can treat influenza but not prevent it. Side effects antiviral drugs that inhibit viral transcription include nausea, anemia and vomiting. Examples of these kind of medications include Tribavarin and Lamivudine, which are administered orally to treat hepatitis B and HIV.
Some Antiviral Drugs Imitate the Immune Reaction Against Viruses
The immune system defends the body against viral infection with many mechanisms including the synthesis and release of interferons alpha and beta from immune cells. These molecules bind to cell surface receptors on virus-infected cells and trigger an immune response against the virus. Interferons stop the action of viruses by inducing enzymes that interfere with the synthesis of viral proteins, into the cell. Interferon alpha can be made commercially using DNA recombinant technology and administered against viral infections. These interferons cannot be administered orally but must be given intravenously. They are used to treat infections caused by the hepatitis B,C, papillomavirus and human herpes viruses.
After replicating inside the cell, the influenza virus leaves the cell by binding to the host cell receptor using the protein hemagglutinin (the H in H1N1). Antiviral drugs such as oseltamivir, sold under the brand name Tamiflu, interferes the virus binding and leaving the host cell. The virus then remains attached and cannot spread the infection.
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