What is Tamiflu (oseltamivir) primarily used for?

Tamiflu, which is the brand name for oseltamivir, is primarily used for the treatment and prevention of influenza viruses, specifically types A and B. It is an antiviral medication that helps reduce the severity and duration of flu symptoms when taken soon after the onset of illness. In addition to treating active influenza infections, it can also be used prophylactically to prevent influenza in individuals who have been exposed to the virus, especially in community outbreaks or high-risk populations.

The medication works by inhibiting the neuraminidase enzyme, which is crucial for the viral replication process. By blocking this enzyme, oseltamivir prevents the virus from spreading within the respiratory tract, thereby alleviating symptoms and shortening the duration of the flu.

Contextually, other options such as Candida infections relate to fungal treatments, PCP refers to a specific type of pneumonia often seen in immunocompromised individuals, and traveler's diarrhea usually involves bacterial or viral infections not treated by Tamiflu. This clear distinction emphasizes the specific role of Tamiflu in addressing influenza, underlining why this is the correct answer.