Antiviral agents.

Only a few agents with antiviral activity are available for regular clinical use. Amantadine hydrochloride is effective in the prophylaxis of influenza A2. Idoxuridine and adenine arabinoside have found application as topical agents in the treatment of herpes simplex keratitis. Adenine arabinoside is also under investigation in the treatment of disseminated infections due to herpes zoster and herpes simplex. Ribavirin, an agent with a wide spectrum of activity in vitro, has not fulfilled expectations in clinical trials. Because of the near eradication of smallpox, methisazone has become less important as a prophylactic agent in smallpox.