Famciclovir is an antiviral medication that is primarily used to treat herpes virus infections such as genital herpes, cold sores, and shingles [1]. The medication works by stopping the spread of the virus in the body. Famciclovir is not approved by the FDA for use in treating other viral infections.

According to Mayo Clinic [2], famciclovir should not be used to treat viral infections such as the flu or the common cold. It is important to note that antiviral medications are specific to the type of virus they target, and using them to treat other types of viral infections may not be effective.

MedlinePlus [3] also notes that famciclovir is not effective against all types of viruses and should not be used to treat infections caused by other viruses.

In conclusion, famciclovir is not approved for use in treating other viral infections. It is specifically designed to treat herpes virus infections and should not be used to treat other types of viral infections such as the flu or the common cold.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/FAMCICLOVIR
[2] https://www.mayoclinic.org/drugs-supplements/acyclovir-oral-route-intravenous-route/precautions/drg-20068393?p=1
[3] https://medlineplus.gov/druginfo/meds/a694038.html