From the Guidelines
Tamiflu (oseltamivir) should be used for the treatment of acute, uncomplicated influenza A and B in patients 2 weeks of age and older, and for the prevention of influenza in patients 1 year of age and older, with the recommended treatment dose being 75mg twice daily for 5 days, initiated within 48 hours of symptom onset 1.
Key Considerations
- The treatment should be started as soon as possible after illness onset and should not be delayed while waiting for a definitive influenza test result, as early therapy provides the best outcomes 1.
- For children, the dosage varies by weight, with specific recommendations for those under 12 months, including term and preterm infants 1.
- The decision to use Tamiflu should be based on clinical judgment, considering underlying conditions, disease severity, time since symptom onset, and local influenza activity 1.
Dosage Recommendations
- For adults and children over 12 months, the recommended treatment dose is 75mg twice daily for 5 days, and for prophylaxis, 75mg once daily for at least 10 days 1.
- For children under 12 months, weight-based dosing is recommended, with adjustments for preterm infants 1.
Special Considerations
- In patients with renal insufficiency, the dose should be adjusted based on creatinine clearance 1.
- Oseltamivir is not recommended for infants under 3 months unless the situation is judged critical, due to limited safety and efficacy data in this age group 1.
- Vomiting is a common side effect of oseltamivir, occurring in approximately 5% of treated patients 1.
- The balance between benefits and harms should be considered when making decisions about the use of oseltamivir for either treatment or chemoprophylaxis of influenza, especially in high-risk groups or those with severe disease 1.
From the FDA Drug Label
Oseltamivir phosphate for oral suspension is indicated for the treatment of acute, uncomplicated illness due to influenza A and B infection in patients 2 weeks of age and older who have been symptomatic for no more than 48 hours. Initiate treatment with oseltamivir phosphate for oral suspension within 48 hours of influenza symptom onset.
Treatment Timing: Oseltamivir (Tamiflu) should be used for the treatment of influenza within 48 hours of symptom onset in patients 2 weeks of age and older.
- The recommended dosage varies by age, with adults and adolescents (13 years and older) taking 75 mg twice daily for 5 days, and pediatric patients (2 weeks of age through 12 years of age) having dosage based on weight or age as outlined in the prescribing information 2.
- Prophylaxis can be initiated within 48 hours following close contact with an infected individual or during a community outbreak.
From the Research
Indications for Tamiflu (Oseltamivir) Use
- Tamiflu 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 3
- The recommended dosage is 75 mg twice daily by mouth for five days 3
Timing of Treatment
- Oseltamivir may increase survival when used within five days of symptom onset in influenza H1N1-infected patients who require ICU admission 3
- There appears to be no benefit in starting treatment more than 48 hours after symptom onset in hospitalized general medicine patients or outpatients infected with either H1N1 or other influenza strains 3
- Early oseltamivir treatment of influenza in children 1-3 years of age, started within 24 hours of symptom onset, provides substantial benefits, including a shortened median time to resolution of illness and reduced parental work absenteeism 4
- Starting oseltamivir within 12 hours of symptom onset in children 1-3 years of age decreases the incidence of acute otitis media by 85% 4
Dosage Considerations
- Double-dose oseltamivir therapy confers no significant survival benefit 3
- Higher-dose oseltamivir treatment (150 mg twice daily) provides no additional benefit in adults hospitalized with influenza A, but may improve virologic response in influenza B 5