What is the current dose of Tamiflu (Oseltamivir)?

Oseltamivir (Tamiflu) Dosing Recommendations

For adults and adolescents ≥13 years, the standard treatment dose is 75 mg orally twice daily for 5 days, and for prophylaxis, 75 mg once daily for at least 10 days post-exposure or up to 6 weeks during community outbreaks. 1

Treatment Dosing

Adults and Adolescents (≥13 years)

• 75 mg orally twice daily for 5 days 2, 1
• Treatment must be initiated within 48 hours of symptom onset for maximum effectiveness 2, 3
• Can be taken with or without food, though taking with meals improves gastrointestinal tolerability 2, 1

Pediatric Patients (1-12 years) - Weight-Based Dosing

The FDA and American Academy of Pediatrics recommend the following weight-based treatment regimens, all given twice daily for 5 days 2, 1:

• ≤15 kg (≤33 lb): 30 mg twice daily 2, 1
• >15-23 kg (>33-51 lb): 45 mg twice daily 2, 1
• >23-40 kg (>51-88 lb): 60 mg twice daily 2, 1
• >40 kg (>88 lb): 75 mg twice daily 2, 1

Infants (<1 year)

• 9-11 months: 3.5 mg/kg per dose twice daily for 5 days 2, 3
• Term infants 0-8 months: 3 mg/kg per dose twice daily for 5 days 2, 3
• Infants ≥2 weeks: 3 mg/kg twice daily for 5 days 1

Preterm Infants (Postmenstrual Age-Based)

Dosing based on postmenstrual age (gestational age + chronological age), all given twice daily 2, 3:

• <38 weeks postmenstrual age: 1.0 mg/kg per dose 2, 3
• 38-40 weeks postmenstrual age: 1.5 mg/kg per dose 2, 3
• >40 weeks postmenstrual age: 3.0 mg/kg per dose 2, 3

Prophylaxis Dosing

Adults and Adolescents (≥13 years)

• 75 mg orally once daily 2, 1
• Duration: At least 10 days following close contact with infected individual 1
• Up to 6 weeks during community outbreak 1
• Up to 12 weeks in immunocompromised patients 1
• Initiate within 48 hours following close contact with infected individual 2, 1

Pediatric Patients (1-12 years)

Same weight-based doses as treatment, but given once daily instead of twice daily for 10 days post-exposure or up to 6 weeks during community outbreak 2, 1:

• ≤15 kg: 30 mg once daily 1
• >15-23 kg: 45 mg once daily 1
• >23-40 kg: 60 mg once daily 1
• >40 kg: 75 mg once daily 1

Infants

• 3-11 months: 3 mg/kg once daily for 10 days 2
• <3 months: Prophylaxis not recommended unless situation is judged critical due to limited safety data 2

Renal Impairment Dosing

Dose adjustments are required for creatinine clearance ≤60 mL/min 2, 1:

Treatment Regimen

• CrCl >60-90 mL/min: 75 mg twice daily for 5 days 1
• CrCl >30-60 mL/min: 30 mg twice daily for 5 days 2, 1
• CrCl >10-30 mL/min: 30 mg once daily for 5 days 2, 1
• ESRD on hemodialysis: 30 mg immediately, then 30 mg after every hemodialysis cycle (not to exceed 5 days) 1
• ESRD on CAPD: Single 30 mg dose 1
• ESRD not on dialysis: Not recommended 1

Prophylaxis Regimen

• CrCl >60-90 mL/min: 75 mg once daily 1
• CrCl >30-60 mL/min: 30 mg once daily 1
• CrCl >10-30 mL/min: 30 mg every other day 2, 1
• ESRD on hemodialysis: 30 mg immediately, then 30 mg after alternate hemodialysis cycles 1
• ESRD on CAPD: 30 mg immediately, then 30 mg once weekly 1

Formulations and Administration

Available Formulations

• Capsules: 30 mg, 45 mg, and 75 mg 2, 3
• Oral suspension: 6 mg/mL when reconstituted from powder 2, 3, 1

Oral Suspension Volumes (6 mg/mL concentration)

• 30 mg dose: 5 mL 2, 1
• 45 mg dose: 7.5 mL 2, 1
• 60 mg dose: 10 mL 2, 1
• 75 mg dose: 12.5 mL 2, 1

Administration Pearls

• Capsules can be opened and contents mixed with liquid if patient cannot swallow whole 2
• If commercial suspension unavailable, pharmacies can compound suspension per package label instructions to 6 mg/mL concentration 2
• Use appropriate oral dosing dispenser that accurately measures volume in mL 1
• For infants <1 year, provide dosing device that can accurately measure small volumes 1

Critical Clinical Considerations

Timing

• Treatment must begin within 48 hours of symptom onset for maximum benefit 2, 3, 1
• Earlier initiation associated with faster symptom resolution 4

Storage of Reconstituted Suspension

• Refrigerated (2-8°C): Use within 17 days 1
• Room temperature (20-25°C): Use within 10 days 1
• Keep in outer carton to protect from light 1

Common Adverse Effects

• Nausea and vomiting are most common, occurring in approximately 1 in 7 patients (vs 1 in 12 on placebo) 4, 5
• Gastrointestinal effects are mild, transient, and less likely when taken with food 2, 4, 5
• Rarely result in discontinuation 5

Drug Interactions

• Avoid live attenuated influenza vaccine (LAIV) within 48 hours before oseltamivir use 2
• Do not use oseltamivir for 14 days after LAIV vaccination 2