Among the anti-infective drugs which have recently been approved for clinical use, the antiviral agents, following the trend set by anti-bacterials (antibiotics) a few decades ago, have taken the lead. In recent years, more than forty antiviral compounds have been formally licensed, more than half of which are used in the treatment of human immunodeficiency virus (HIV) infections (AIDS). Others have been licensed for the treatment of herpesvirus infections, hepatitis B and C, and influenza. For other virus infections, i.e. pox (variola, vaccinia), hemorrhagic fever virus, picornavirus, flavivirus, papilloma- and adenovirus infections, effective antiviral drugs still have to be developed or submitted to clinical trials. Even for those virus infections that can already be controlled by therapeutic modalities, the search for additional molecular targets and new treatment strategies should be pursued. The development of antiviral agents requires a multidisciplinary approach encompassing many different fields, such as molecular modeling, medicinal chemistry, biochemistry, pharmacology, toxicology and clinical medicine. Most importantly, the development of antiviral agents may learn from (and should not been dissociated from) other anti-infectives, in particular those compounds targeted at bacterial infections (i.e. tuberculosis) and protozoal infections (i.e. malaria) and other parasitic diseases, as evidence is growing for compounds trespassing these borders, both from a structure-activity relationship (SAR) and mode of action viewpoint.
