ANTIVIRAL DRUGS

substances that interfere with or corrupt the normal functioning of viruses. These substances may act by blocking host-cell enzyme systems, which are required for viral reproduction. May also work by blocking signals carried in messenger RNA, or by uncoating and dismembering the nucleic acid molecule of the virus. Antiviral drugs may be difficult to manage in clinical practice because these chemicals may also interfere with the patient's normal cell functioning. Antivirals may occasionally interact with natural substances in human tissues and create unexpected benefits, as with amantadine, which can be used as an Antiparkinsonian agent.