Antiviral drugs are medicines that cure or control virus infections.Antivirals are used to treat infections caused by viruses. Unlike antibacterial drugs, which may cover a wide range of pathogens, antiviral agents tend to be narrow in spectrum, and have limited efficacy.
Viruses represent a large group of infective agents that are composed of a core of nucleic acids, either RNA or DNA, surrounded by a layer of protein. They are not really living organisms according to general understanding, since they lack the cell membrane that is associated with living cells. Viruses can reproduce only inside a living cell, and they cause many diseases. Viruses are not normally affected by antibiotics but a small number of viruses can either be destroyed or have their growth stopped by drugs.