From the Guidelines
Oseltamivir (Tamiflu) is still appropriate for treatment up to 5 days after symptom onset, with the most recent and highest quality study 1 supporting its use in this timeframe.
Treatment Regimen
The recommended treatment regimen for influenza with oseltamivir is as follows:
- Adults: 75 mg twice daily for 5 days
- Children:
- Less than 15 kg: 30 mg twice daily for 5 days
- 15-23 kg: 45 mg twice daily for 5 days
- 23-40 kg: 60 mg twice daily for 5 days
- Over 40 kg: 75 mg twice daily for 5 days
Important Considerations
- Treatment should ideally begin within 48 hours of symptom onset for maximum effectiveness, though it may still provide some benefit when started later 1.
- Patients with severe renal impairment (creatinine clearance less than 30 mL/min) require dose reduction to 75 mg once daily 1.
- Oseltamivir works by inhibiting viral neuraminidase, preventing the release of new virus particles from infected cells, thereby reducing viral replication and shortening illness duration by approximately 1-1.5 days 1.
- Common side effects include nausea and vomiting, which can be minimized by taking the medication with food 1.
- While oseltamivir treats influenza symptoms, supportive care including rest, hydration, and fever-reducing medications remains important for patient comfort during recovery 1.
From the FDA Drug Label
The recommended oral dosage of oseltamivir phosphate for oral suspension for treatment of influenza in adults and adolescents 13 years and older is 75 mg twice daily (12. 5 mL of oral suspension twice daily) for 5 days.
The treatment with oseltamivir (Tamiflu) is still appropriate for 5 days.
- Key points:
- Initiate treatment within 48 hours of influenza symptom onset.
- The recommended duration of treatment is 5 days.
- Dosage is 75 mg twice daily for adults and adolescents 13 years and older. 2
From the Research
Oseltamivir Treatment Regimen
- The recommended treatment regimen for influenza with oseltamivir is 75 mg twice daily for 5 days 3.
- Studies have shown that oseltamivir reduces the duration of the disease by up to 1.5 days and the severity of illness by up to 38% compared with placebo when initiated within 36 hours of symptom onset 3.
- The treatment is most effective when started within 48 hours of symptom onset, and there is no significant 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 4.
Duration of Treatment
- The standard duration of oseltamivir treatment is 5 days 3, 4.
- There is limited evidence to support the use of oseltamivir for longer than 5 days in any patient population, except possibly in critically ill H1N1-infected ICU patients, who may benefit from extended treatment in some cases 4, 5.
Special Considerations
- Oseltamivir is generally well-tolerated, but may lead to neuropsychiatric events and bleeding 6.
- Dose adjustment for oseltamivir should be based on creatinine clearance and body weight in pediatric patients with renal failure 6.
- Oseltamivir-resistant influenza virus has been associated with the H275Y mutation in the influenza A(H1N1)pdm09 virus, while most strains are still sensitive to oseltamivir 6.