Tamiflu (Oseltamivir Phosphate)
Also sold as: Tamiflu, Antiflu, Fluvir, Osiflu, Virobin
Pregnancy
Cat C
Lactation
Safe
Schedule
H
Forms
Capsule 30mg, 45mg, 75mg +1
Indications
- Treatment of influenza A and B (within 48 hours of symptom onset — start as early as possible)
- Post-exposure prophylaxis of influenza (household contact with confirmed case)
- Seasonal prophylaxis (immunocompromised, high-risk)
Adult Dosing
Treatment of influenza
75 mg PO BD for 5 days
Start within 48 hours of symptom onset — greatest benefit if started within 12–24 hours. Reduces duration by ~1 day and severity.
Post-exposure prophylaxis
75 mg PO once daily for 10 days (household contact)
Start within 48 hours of exposure
Seasonal prophylaxis (immunocompromised)
75 mg PO once daily for 6–12 weeks during influenza season
Specialist directed
Pediatric Dosing
Oral suspension preferred for children. Full-term neonates (specialist use — pandemic or severe illness): 3 mg/kg/dose BD.
Renal Dose Adjustment
| CrCl / eGFR | Dose Adjustment |
|---|---|
| CrCl 10–30 mL/min (treatment) | 75 mg once daily for 5 days |
| CrCl 10–30 mL/min (prophylaxis) | 30 mg once daily or 75 mg every other day |
| CrCl < 10 mL/min or ESRD | No specific recommendation — use with caution; limited data |
Hepatic Adjustment
No dose adjustment required — hepatically converted to active oseltamivir carboxylate but adjustment not necessary
Pregnancy & Lactation
Pregnancy: Category C
Influenza is more severe in pregnancy — benefit of treatment outweighs theoretical risk. WHO and national guidelines recommend treatment of pregnant women with influenza. Start within 48 hours of symptoms.
Lactation: Safe
Excreted in small amounts in breast milk; generally considered acceptable. WHO recommends treatment of breastfeeding mothers with influenza — continue breastfeeding.
Top Drug Interactions
| Interacting Drug | Effect | Severity |
|---|---|---|
| Probenecid | Increases oseltamivir levels (reduces renal secretion) — not clinically significant at standard doses but noted | Minor |
| Live attenuated influenza vaccine (LAIV — intranasal) | Oseltamivir may reduce LAIV efficacy — avoid LAIV 48 hours before to 2 weeks after oseltamivir | Moderate |
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Side Effects
Common
- Nausea (most common — 10–20%)
- Vomiting
- Diarrhoea
- Headache
- Abdominal pain
Serious / Discontinue If
- Neuropsychiatric events (rare — confusion, delirium, hallucinations, self-harm — especially in children/adolescents; Japanese reports; monitor closely)
- Anaphylaxis (rare)
Contraindications
- Hypersensitivity to oseltamivir
Available Indian Brands
| Brand | Manufacturer | Price (approx) |
|---|---|---|
| Antiflu 75mg | Cipla | 10 cap ₹685 |
| Fluvir 75mg | Hetero | 10 cap ₹585 |
| Osiflu 75mg | Sun Pharma | 10 cap ₹635 |
| Tamiflu 75mg | Roche | 10 cap ₹1,850 |
Monitoring Required
- Symptom improvement within 48–72 hours
- Oxygen saturation in severe influenza
- Neuropsychiatric status (especially children — behaviour changes, confusion)
- Renal function in CKD patients
Patient Counseling Points
- Start as soon as possible — works best within 24–48 hours of first symptoms
- Take with food to reduce nausea
- Complete the full 5-day course even if you feel better — prevents viral rebound
- Not a substitute for influenza vaccine — still get vaccinated annually
- Parents of children: watch for unusual behaviour, confusion, or self-harm — rare but reported
- Reduces duration of flu by about 1 day and reduces severity — it does not cure flu but reduces complications
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Clinically reviewed by: Dr. Rajesh Kulkarni, MD (Infectious Diseases), Consultant Infectious Disease Specialist
Last reviewed: 2026-04-01
References
- WHO Influenza Treatment Guidelines
- IDSA Influenza Guidelines 2019
- BNF — Oseltamivir
- CDC Influenza Antiviral Medications