What is the dosing and administration guidelines for intravenous (IV) oseltamivir (Tamiflu) for influenza treatment?

Intravenous Oseltamivir (Tamiflu) Does Not Exist

Oseltamivir (Tamiflu) is NOT available in an intravenous formulation—it is only administered orally as capsules or oral suspension. 1

The Confusion: Peramivir is the IV Neuraminidase Inhibitor

You may be thinking of peramivir, which is the intravenous neuraminidase inhibitor approved for influenza treatment:

Peramivir IV Dosing 1:

• Adults: 600 mg as a single IV infusion over 15-30 minutes
• Children 13-17 years: 600 mg as a single IV infusion over 15-30 minutes
• Children 2-12 years: 12 mg/kg (maximum 600 mg) as a single IV infusion over 15-30 minutes
• Peramivir is NOT approved for chemoprophylaxis 1

Oseltamivir Administration Routes

Oseltamivir is exclusively oral and comes in two formulations 1, 2:

Available Formulations:

• Capsules: 30 mg, 45 mg, and 75 mg 1, 2
• Oral suspension: Powder reconstituted to 6 mg/mL concentration 1, 2

Standard Oseltamivir Treatment Dosing (5 days) 1, 2:

Adults and adolescents ≥13 years: 75 mg orally twice daily

Children ≥12 months (weight-based):

• ≤15 kg: 30 mg twice daily

• 15-23 kg: 45 mg twice daily

• 23-40 kg: 60 mg twice daily

• 40 kg: 75 mg twice daily

Infants 9-11 months: 3.5 mg/kg per dose twice daily 1

Term infants 0-8 months: 3 mg/kg per dose twice daily 1

Preterm infants (based on postmenstrual age) 1:

• <38 weeks: 1.0 mg/kg twice daily
• 38-40 weeks: 1.5 mg/kg twice daily

• 40 weeks: 3.0 mg/kg twice daily

Critical Administration Details

Timing is Everything:

• Treatment must be initiated within 48 hours of symptom onset for maximum benefit 2, 3
• Starting within 12 hours reduces illness duration by an additional 74.6 hours compared to starting at 48 hours 3

Renal Dose Adjustments 1, 2:

• CrCl 10-30 mL/min (treatment): 75 mg once daily for 5 days
• CrCl 10-30 mL/min (prophylaxis): 30 mg once daily for 10 days OR 75 mg every other day for 10 days (5 doses)
• Patients on CVVHDF: Reduce dose and monitor drug levels due to 4-5 fold accumulation 4

Administration Tips:

• Can be given with or without food, though taking with meals improves GI tolerability 1, 2, 3
• If commercial suspension unavailable, pharmacies can compound it to 6 mg/mL concentration 1

Common Pitfall

Do not confuse oseltamivir with peramivir. If you need an IV neuraminidase inhibitor for a patient who cannot take oral medications, peramivir is your only option. 1