Oseltamivir is an antiviral medication that blocks the neuraminidase enzyme on the surface of influenza viruses. By preventing the release of newly formed viral particles, the drug limits the spread of infection within the respiratory tract. The active ingredient is absorbed into the bloodstream and reaches infected cells where it exerts its inhibitory effect. This action reduces the duration and severity of flu symptoms when the drug is taken early in the course of illness. The pharmacological mechanism involves competitive inhibition of the enzyme that cleaves sialic acid, thereby halting viral budding and dissemination. Overall the medication supports the body's immune response by lowering viral load and allowing faster recovery.

Oseltamivir is an oral antiviral drug used for treatment and prevention of influenza infection. It is marketed as tamiflu and belongs to the class of neuraminidase inhibitors. Its primary pharmacological action involves selective inhibition of the viral neuraminidase enzyme. By blocking neuraminidase, Oseltamivir prevents release of newly formed viral particles from infected cells. This inhibition reduces viral replication and spread causing shorter duration and severity of symptoms. The active metabolite is eliminated mainly through renal excretion after conversion in the liver. Its systemic activity provides a targeted therapeutic option without broad immunosuppression or direct cytotoxicity

Headache often appears as a mild discomfort. Fatigue describes a feeling of tiredness that may last several days. Fever reflects a temporary rise in body temperature. Muscle pain can affect sore areas of the body. Chills involve sudden shaking or feeling cold. Nausea may cause a sensation of stomach upset. Pain at the injection site typically occurs near where the shot is given. Swelling of lymph nodes can be noticed in some individuals.

The most common side effects include headache, facial flushing, and mild dizziness. Some people may experience nasal congestion or a runny nose. Skin redness or itching can occur after application. Muscle aches are reported in a small portion of users. Digestive discomfort such as stomach upset may appear occasionally. Rarely, temporary vision changes have been noted. These effects are usually mild and short-lived. They tend to improve with continued use or adjustment of dosage.