Summary: Introduction. Influenza, an acute viral respiratory disease, remains one of the most significant seasonal threats to public health, placing a heavy burden on healthcare systems and high-risk populations. Oseltamivir, an oral neuraminidase inhibitor, is the first-line treatment and post-exposure prophylaxis for influenza in adults and children.
Objective. To provide a practical summary of the mechanism of action, clinical efficacy, safety pro-file, contraindications, interactions, and dosage of oseltamivir in light of current guidelines (WHO, CDC, IDSA) and key clinical studies.
Discussion. Oseltamivir selectively inhibits the neuraminidase of influenza A and B viruses, limiting the release of virions and the spread of infection. Meta-analyses and randomized trials have demonstrated that early treatment reduces the duration of symptoms, decreases contagiousness and disease severity, and lowers the risk of complications, including otitis media in children, as well as the risk of death among hospitalized patients. The drug is well tolerated; the most common side effects are nausea and vomiting. Reports of neuropsychiatric events are inconsistent; reviews do not confirm an increase in risk in an unequivocal manner. Post-exposure prophylaxis with oseltamivir significantly reduces the risk of influenza in the home and care institutions, provided it is started within 48 hours of exposure.
Conclusions. Oseltamivir remains the cornerstone of effective treatment of influenza and its post-exposure prophylaxis. Early initiation of treatment and proper patient selection are key to good clinical outcomes. International and European recommendations recommend the use of oseltamivir, particularly in high-risk patients, hospitalized patients, and during epidemic outbreaks.