From the Guidelines
Tamiflu (oseltamivir) dosing depends on age, weight, and whether it's being used for treatment or prevention of influenza, with the most recent guidelines from 2019 recommending the following dosages. For treatment in adults and adolescents 13 years and older, the standard dose is 75 mg twice daily for 5 days, as indicated in the 2019 guidelines 1. Children's treatment doses are weight-based:
- 30 mg twice daily for those weighing less than 15 kg
- 45 mg twice daily for 15-23 kg
- 60 mg twice daily for 23-40 kg
- 75 mg twice daily for over 40 kg, all for 5 days. For prevention (prophylaxis), adults and teens take 75 mg once daily for 10 days after exposure or up to 6 weeks during community outbreaks. Children receive the same weight-based doses as treatment but given once daily instead of twice.
- For infants 9–11 months old, the dose is 3.5 mg/kg per dose, twice daily for treatment and 3.5 mg/kg per dose, once daily for chemoprophylaxis.
- For term infants 0–8 months old, the dose is 3 mg/kg per dose, twice daily for treatment and 3 mg/kg per dose, once daily for chemoprophylaxis for infants 3–8 months old. Dosage should be reduced for patients with kidney impairment (creatinine clearance between 10-30 ml/min), with a recommended dose of 75 mg once daily for 5 days for treatment and 30 mg once daily for 10 days after exposure or 75 mg once every other day for 10 days after exposure (5 doses) for chemoprophylaxis 1. The most recent and highest quality study from 2019 provides the basis for these recommendations 1.
From the FDA Drug Label
2 DOSAGE AND ADMINISTRATION
2.1 Dosage and Administration Overview ... 2.2 Recommended Dosage for Treatment of Influenza ... Adults and Adolescents (13 years of age and older) 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. ... Table 1 Oseltamivir Phosphate for Oral Suspension Dosage Recommendations in Pediatric Patients for Treatment and Prophylaxis of Influenza
Weight Treatment Dosage for 5 days Prophylaxis Dosage for 10 days* Volume of Oral Suspension (6 mg/mL) for each Dose† Number of Bottles of Oral Suspension to Dispense Patients from 2 Weeks to less than 1 Year of Age Any weight 3 mg/kg twice daily Not applicable 0.5 mL/kg§ Patients 1 to 12 Years of Age Based on Body Weight 15 kg or less 30 mg twice daily 30 mg once daily 5 mL 1 bottle 15.1 kg to 23 kg 45 mg twice daily 45 mg once daily 7.5 mL 2 bottles 23.1 kg to 40 kg 60 mg twice daily 60 mg once daily 10 mL 2 bottles 40.1 kg or more 75 mg twice daily 75 mg once daily 12.5 mL 3 bottles
The Tamiflu dosages chart is as follows:
- Adults and Adolescents (13 years and older): 75 mg twice daily for 5 days
- Pediatric Patients:
- 2 weeks to less than 1 year: 3 mg/kg twice daily
- 1 to 12 years:
- 15 kg or less: 30 mg twice daily
- 15.1 kg to 23 kg: 45 mg twice daily
- 23.1 kg to 40 kg: 60 mg twice daily
- 40.1 kg or more: 75 mg twice daily 2
From the Research
Tamiflu Dosage Information
- The standard recommended dosage of oseltamivir (Tamiflu) is 75 mg twice daily by mouth for five days 3.
- There is no significant benefit in doubling the dose of oseltamivir in hospitalized patients or outpatients 3, 4.
- Oseltamivir may increase survival when used within five days of symptom onset in influenza H1N1-infected patients who require ICU admission 3.
- The use of oseltamivir for longer than five days is not well supported by evidence, except possibly for critically ill H1N1-infected ICU patients 3, 4.
Special Considerations
- The effectiveness of oseltamivir in preventing hospitalization and death is well established, with a reduced risk of pneumonia and hospitalization by 44% and 63%, respectively 5.
- Inhaled zanamivir is not inferior to oral oseltamivir in preventing influenza-related hospitalization or death for patients whose conditions do not require hospitalization within 2 days 5.
- The incidence of oseltamivir resistance is around 2.6%, with a higher incidence rate among influenza A patients, especially for H1N1 subtype influenza 6.
- Zanamivir resistance has been rarely reported to date 6.