Which of the following antiviral medications is recommended if influenza is diagnosed within the first 48 hours of symptoms?

Oseltamivir is an antiviral medication that is specifically indicated for the treatment of influenza, particularly when symptoms have started within the first 48 hours. It belongs to a class of drugs known as neuraminidase inhibitors, which work by blocking the function of the neuraminidase enzyme on the surface of the influenza virus. This action helps to prevent the virus from spreading throughout the body and reduces the duration of symptoms.

Starting treatment within the first 48 hours of symptom onset is crucial because antiviral medications are most effective when administered early in the course of the illness. Delaying treatment beyond this window may decrease the effectiveness of the medication and prolong the recovery period.

Other antiviral medications listed do not have the same indication for treating influenza. Ribavirin is mainly used for respiratory syncytial virus (RSV) infections and hepatitis C, while acyclovir is used to treat herpes virus infections, and zidovudine is an antiretroviral medication for HIV. Thus, oseltamivir is the appropriate choice for influenza treatment within the first 48 hours after symptoms appear.