From the Guidelines
Oseltamivir (Tamiflu) Overview
Oseltamivir, commonly known by its brand name Tamiflu, is an antiviral medication used to treat and prevent influenza A and B viruses [@\1@, @\2@, @\3@, @\4@, @\5@].
Mechanism and Efficacy
It works by inhibiting the neuraminidase enzyme on the surface of influenza viruses, preventing the release of new viral particles from infected cells. When administered within 2 days of illness onset to otherwise healthy adults, oseltamivir can reduce the duration of uncomplicated influenza A and B illness by approximately 1 day compared with placebo [@\1@].
Resistance and Usage
However, there have been reports of increased resistance to oseltamivir among certain influenza strains, such as A (H1N1) viruses [@\3@]. Despite this, oseltamivir remains a recommended antiviral agent for the prevention and treatment of influenza, alongside zanamivir [@\3@].
Clinical Applications
Oseltamivir has been shown to reduce the risk of pneumonia and hospital admissions in patients with laboratory-confirmed influenza [@\2@, @\4@]. Additionally, it has been found to decrease the incidence of otitis media in children and improve lung function in children with asthma [@\2@, @\4@].
Limitations
It's worth noting that there is limited data on the effectiveness of oseltamivir in preventing serious influenza-related complications or in treating influenza in certain high-risk populations, such as children under 1 year of age [@\2@, @\4@].
From the FDA Drug Label
Oseltamivir phosphate for oral suspension is a prescription medicine used to: treat the flu (influenza) in people 2 weeks of age and older who have had flu symptoms for no more than two days. prevent the flu in people who are 1 year of age and older.
Oseltamivir (Tamiflu) is an antiviral drug with activity against influenza virus. It is used to treat and prevent influenza in people 2 weeks of age and older. The medication works by inhibiting the replication of the influenza virus.
- Key uses:
- Treatment of influenza in people 2 weeks of age and older
- Prevention of influenza in people 1 year of age and older
- Important note: Oseltamivir phosphate for oral suspension does not treat or prevent illness that is caused by infections other than the influenza virus. 1
From the Research
Definition and Mechanism of Oseltamivir (Tamiflu)
- Oseltamivir is a prodrug of oseltamivir carboxylate, a potent and selective inhibitor of the neuraminidase glycoprotein essential for replication of influenza A and B viruses 2.
- It is an orally administered antiviral for the treatment and prevention of influenza A and B infections 3.
Clinical Efficacy
- Oseltamivir has been shown to reduce the duration of symptomatic illness and hasten the return to normal levels of activity when initiated promptly in patients with naturally acquired influenza 2, 4.
- It has also been found to be effective in preventing the development of naturally acquired influenza by >70% compared with placebo in unvaccinated otherwise healthy adults 2.
- Oseltamivir has been shown to be effective in the treatment of children with influenza, and data suggest that it may also be of use in high-risk populations such as the elderly or those with chronic cardiac or respiratory disease 2, 4.
Safety Profile
- Oseltamivir is generally well tolerated, with nausea and vomiting being the most commonly reported adverse events 2, 4.
- Gastrointestinal events are usually mild and transient, and both nausea and vomiting are less likely when oseltamivir is taken with food 2.
- There have been reports of neuropsychiatric adverse events associated with oseltamivir, particularly in children and adolescents 5.
Usage and Recommendations
- Oseltamivir is recommended by the World Health Organization (WHO) for use in the clinical management of pandemic and seasonal influenza of varying severity, and as the primary antiviral agent for treatment of avian H5N1 influenza infection in humans 3.
- The standard dosing recommendations for oseltamivir are 75 mg twice daily by mouth for five days, and it is indicated for the treatment of uncomplicated influenza in patients two weeks of age or older who have been symptomatic for no more than two days 6.