Antiviral agents.

Amantadine is well established as the preferred antiviral agent for the prophylaxis of influenza A and may also be beneficial therapeutically when used early in the course of the disease. Idoxuridine is applicable only in the treatment of herpetic keratitis. Currently, acyclovir is the most effective agent for the treatment of herpes simplex and varicella-zoster virus infections. Ribavirin has recently been released for use in aerosol form for severe respiratory syncytial virus infections that occur in infants and young children. Vidarabine, which previously was the drug of choice in the treatment of severe herpetic infections, has now been replaced by the more effective acyclovir. Ganciclovir, an experimental agent, has shown promise against cytomegalovirus infections in patients who have undergone kidney or liver transplantation, but its effects are only temporary in patients who have undergone bone marrow transplantation and patients with acquired immunodeficiency syndrome (AIDS) who have cytomegalovirus infections.