Final answer:
Amantadine was primarily used against Influenza A but now is less common due to drug resistance and side effects. Ribavirin, on the other hand, is used for a variety of viral infections, including RSV and viral hemorrhagic fevers. Acyclovir is effective against herpes simplex viruses, managing symptoms but not curing the infection.
Step-by-step explanation:
Amantadine is an antiviral medication initially used for the treatment of Influenza A. However, due to increasing resistance, its use for flu has become limited. Instead, it has found some application in the treatment of Parkinson's disease due to its influence on neurotransmitters like dopamine and NMDA.
Antiviral drugs such as Ribavirin have been used to treat a variety of viral infections including severe Respiratory Syncytial Virus (RSV) infections and certain viral hemorrhagic fevers. Ribavirin works by interfering with the replication of RNA viruses. Unlike amantadine, which was once a prominent drug for influenzas, newer antivirals like oseltamivir (Tamiflu) have shown efficacy in treating influenza by preventing viral escape from host cells.
Other antivirals, like acyclovir, target herpes simplex viruses by reducing the number and duration of episodes. Although they cannot cure latent infections, these medications aid in managing symptoms more effectively.