Antiviral drugs are those used to treat viral infections such as herpes simplex, herpes zoster, cytomegalovirus (CMV), influenza, AIDS, and certain AIDS related infections.

Viral diseases are harder to control than bacterial diseases due to their mode of operation. A virus is a small packet of infectious nucleic acid material surrounded by a protein coat. The nucleic acid is either DNA or RNA. This nucleic acid must use the machinery of the host's cells to reproduce and successfully complete the life cycle of the virus. With some viruses as soon as the RNA enters the cell it is translated and more viral particles are released; with others the nucleic material must first incorporate itself into the nucleic material of the host. This latter category of viruses is the retroviruses. An example of a retrovirus is Human Immunodeficiency Virus (HIV) which causes AIDS. An intimate knowledge of...