Generic
Oseltamivir
7 brands available in the market
At a glance
Oseltamivir is an antiviral used for treatment and prevention of influenza A and B. It inhibits neuraminidase enzyme to prevent release of viruses from infected host cells.
Description
Oseltamivir is an ethyl ester prodrug requiring ester hydrolysis for conversion to the active form, oseltamivir carboxylate. It inhibits influenza virus neuraminidase to alter virus particle aggregation and release, preventing viral replication.
Indications
- Treatment of influenza A and B (within 2 days of symptom onset)
- Prophylaxis of influenza A and B (within 2 days of exposure)
Therapeutic class
Respiratory Viral Infections (Influenza)
Pharmacological class
Neuraminidase Inhibitor
Pharmacology
Oseltamivir is converted to active oseltamivir carboxylate which inhibits influenza virus neuraminidase enzyme, preventing virus release from infected cells and viral replication.
Mechanism of action
Treats and prevents influenza by inhibiting virus spread.
Dosage
Adult Dose (Oral):
- Treatment: 75 mg twice daily for 5 days
- Prophylaxis: 75 mg once daily for at least 10 days (up to 6 weeks in outbreak)
Pediatric Dose (Weight-based):
- Treatment: ≤15 kg: 30 mg; 15-23 kg: 45 mg; 23-40 kg: 60 mg; >40 kg: 75 mg — all twice daily for 5 days
- Prophylaxis: ≤15 kg: 30 mg; 15-23 kg: 45 mg; 23-40 kg: 60 mg; >40 kg: 75 mg — all once daily for 10 days
Administration
- May be taken with or without food (food improves tolerability)
- Swallow capsule whole; do not chew, crush or break
- Take at the same time each day
Missed dose
If you miss a dose, take it as soon as you remember; skip if it's almost time for next dose; do not double the dose.
Side effects
Common Side Effects:
- Nausea
- Vomiting
- Abdominal pain
- Diarrhea
Uncommon (<1%): Unstable angina, anemia, pseudomembranous colitis, pneumonia, peritonsillar abscess
Precautions & warnings
- Not effective for illness caused by agents other than influenza A and B
- Efficacy not established if treatment starts after 40 hours of symptoms
- May interact with live attenuated influenza vaccine
- Dose adjustment in severe renal impairment
Contraindications
- Hypersensitivity
- Severe renal impairment (caution)
Drug interactions
- May potentially inhibit replication of influenza virus in live/attenuated influenza virus vaccine
Food interactions
Safety with alcohol not known; consult doctor.
Use in pregnancy
Use in Pregnancy: Oseltamivir may be unsafe during pregnancy (Category C); animal studies show evidence of fetal harm.
Pregnancy Category: C — always consult a doctor before taking during pregnancy.
Use in lactation
Use in Lactation: Oseltamivir is probably safe during breastfeeding; no significant risk to baby.
Pediatric use
Safety and efficacy not studied in children under 1 year; indicated for children 1 year+.
Geriatric use
Elderly may require dose adjustment.
Renal / hepatic impairment
Renal Impairment: CrCl 10-30: 30 mg once daily; CrCl 30-60: 30 mg twice daily; Dialysis: 30 mg after each session.
Hepatic Impairment: Caution in severe liver disease; no dose adjustment in mild-moderate.
Overdose effects
Overdose: Nausea and vomiting; symptomatic treatment.
Storage conditions
Store at 25°C; Reconstituted suspension: Store at 2-8°C for up to 17 days or at 25°C for up to 10 days; do not freeze.
Chemical structure
Oseltamivir