Tamiflu (Oseltamivir)
Dose Calculator
Calculate influenza treatment doses for full-term infants, children, adolescents and adults using 60 mg/5 mL suspension.
Enter the patient’s weight and age. Age is required because the dosing method differs for infants younger than 1 year, children aged 1–12 years, and patients aged 13 years or older.
Oseltamivir treatment dose
Infant calculated dose exceeds 30 mg/dose
This calculator intentionally does not generate an automatic mL dose in this situation. Verify the infant dose using the current clinical reference and individual patient factors.
Oseltamivir treatment dosing
Oral treatment doses for 5 days.
| Patient | Dose | 60 mg/5 mL | Regimen |
|---|---|---|---|
| Full-term infant <1 year | 3 mg/kg/dose | Calculated from weight | BD × 5 days |
| 1–12 years ≤15 kg | 30 mg | 2.5 mL | BD × 5 days |
| 1–12 years >15–23 kg | 45 mg | 3.75 mL | BD × 5 days |
| 1–12 years >23–40 kg | 60 mg | 5 mL | BD × 5 days |
| 1–12 years >40 kg | 75 mg | 6.25 mL | BD × 5 days |
| ≥13 years / adult | 75 mg | 6.25 mL | BD × 5 days |
Infant safety rule: the calculator uses 3 mg/kg/dose for full-term infants younger than 1 year. If the calculated dose exceeds 30 mg, automatic dose and volume output is withheld for manual clinical verification.
Important: the 30 mg level above is a SetelDoc manual-review trigger, not a guideline-defined maximum infant dose. Premature infants and patients with renal impairment are outside this calculator.
Paediatric Dose Calculator Demo
If you want a faster clinic workflow, use the full SetelDoc Dose Calculator with over 30 medicines.
When to consider oseltamivir treatment
Start early
Clinical benefit is greatest when oseltamivir is started as soon as possible, particularly within 48 hours of symptom onset.
Priority patients
Severe, complicated, progressive, hospitalised or higher-risk influenza warrants prompt antiviral consideration when clinically indicated.
Reassess red flags
Respiratory distress, hypoxia, dehydration, shock, altered consciousness, persistent vomiting or rapidly progressive illness should prompt escalation.
Before using the calculated dose
Tamiflu / oseltamivir FAQ
What dose is used for a full-term infant under 1 year?
This calculator uses 3 mg/kg per dose twice daily for 5 days in full-term infants younger than 1 year.
Why does the calculator stop above 30 mg in an infant?
This is a SetelDoc safety rule. A calculated infant dose above 30 mg is withheld for manual verification rather than automatically converted to mL. The 30 mg threshold is not presented as a guideline maximum.
What is the Tamiflu dose for a child weighing 18 kg?
For a child aged 1–12 years weighing more than 15 kg and up to 23 kg, the treatment dose is 45 mg BD for 5 days. With 60 mg/5 mL suspension, this equals 3.75 mL BD × 5 days.
What is the Tamiflu dose for a child weighing 25 kg?
For a child aged 1–12 years weighing more than 23 kg and up to 40 kg, the treatment dose is 60 mg BD for 5 days. With 60 mg/5 mL suspension, this equals 5 mL BD × 5 days.
What concentration does this calculator use?
All volume calculations use oseltamivir 60 mg/5 mL oral suspension.
Can oseltamivir still be started after 48 hours?
Benefit is greatest when treatment is started early. Later treatment may still be appropriate in selected severe, progressive, hospitalised or higher-risk patients.
Can I use this calculator for renal impairment?
No. Patients with renal impairment may require a different dose or dosing interval and should be managed using the appropriate renal-adjustment reference.
Can this calculator be used for prophylaxis?
No. The calculator is intentionally limited to treatment dosing.
Clinical references
- Ministry of Health Malaysia — Formulari Ubat KKM: Oseltamivir — Malaysian treatment dose bands for children aged 1 year and older and the standard adolescent/adult regimen.
- CDC — Influenza Antiviral Medications: Summary for Clinicians — treatment dosing including full-term infants younger than 1 year.
For healthcare professionals. This calculator supports but does not replace clinical judgement. Verify the indication, renal function, formulation and individual patient factors before prescribing.