Antiviral:An antiviral is a substance that either destroys viruses or suppresses their ability to replicate, thereby preventing them from multiplying. For instance, amantadine (Symmetrel) is a man-made compound that works by stopping the replication of the A virus. It was typically used to reduce the severity of the illness, especially in high-risk groups like immunocompromised individuals or those in nursing homes. However, amantadine has been largely replaced by safer alternatives like oseltamivir (Tamiflu) and zanamivir (Relenza), which have fewer adverse effects.The progress in developing antivirals has been much slower compared to antibiotics. Viruses are essentially genetic material, either DNA or RNA, sometimes with a few enzymes, enclosed in a protein shell. Technically not being alive makes viruses challenging to eliminate. Additionally, they replicate by taking over the host cell's machinery, making it difficult to target the virus without harming the host cell. Some viruses can also remain inactive in the body without replicating, thereby evading drugs that target replication.The antivirals that have been created are often not as effective as desired. Viruses can reproduce quickly and often inaccurately, leading to mutations that can make them drug-resistant. For rapidly spreading viral infections like the flu or a common cold, a drug must be highly potent to have any effect before the illness naturally subsides.