Oseltamivir
Indications
Oseltamivir is used for:
Influenza
Adult Dose
Oral
Treatment of Influenza A and B
Adult: 75 mg bid for 5 days. Initiate w/in 2 days of onset of symptoms.
Prophylaxis of influenza A and B
Adult: 75 mg once daily for at least 10 days. Initiate w/in 2 days of exposure. For community outbreak: May continue dosing for up to 6 wk.
Child Dose
Influenza A and B Treatment
<2 weeks: Safety and efficacy not established for treatment
Aged 2 weeks to <1 year
3 mg/kg PO BID x5 days
>1 year
<15 kg: 30 mg PO q12hr x5 days
15-23 kg: 45 mg PO q12hr x5 days
23-40 kg: 60 mg PO q12hr x5 days
>40 kg: 75 mg PO q12hr x5 days
Dosing considerations
Start within 24-48 hours of symptom onset
Influenza A and B Prophylaxis
<1 year: Safety and efficacy not established for prophylaxis
?1 year
<15 kg: 30 mg PO qDay x10 days
15-23 kg: 45 mg PO qDay x10 days
23-40 kg: 60 mg PO qDay x10 days
>40 kg: 75 mg PO qDay x10 days
Dosing considerations
Start within 2 days of exposure
Renal Dose
Renal impairment: Haemodialysis patient: 30 mg after each dialysis session. Peritoneal dialysis patient: 30 mg as a single dose.
CrCl (ml/min) Dosage Recommendation
<10 Not recommended.
>10-30 30 mg once daily.
>30-60 30 mg bid.
Administration
May be taken with or without food. May be taken w/ meals to reduce GI discomfort. Cap may be opened & mixed w/ sweetened food products eg chocolate syr, sweetened condensed milk, apple sauce or yogurt. Swallow mixture immediately after preparation.
Contra Indications
Hypersensitivity. Severe renal impairment.
Precautions
Patient w/ resp disease, chronic cardiac disease. Renal and severe hepatic impairment. Immunocompromised patient. Childn. Pregnancy and lactation. Monitoring Parameters Monitor closely for signs and symptoms of behavioural changes.
Lactation: Unknown; use caution
Pregnancy-Lactation
Interactions
May potentially inhibit replication of influenza virus in live/attenuated influenza virus vaccine.
Adverse Effects
Side effects of Oseltamivir :
1-10%
Abdominal pain, Conjunctivitis, Ear disorder, Epistaxis, Insomnia, Nausea, Vomiting, Vertigo
<1%
Aggravation of diabetes, Anemia, Arrhythmia, Confusion, Delirium, Hemorrhagic colitis, Hepatitis, Humerus fracture, Peritonsillar abscess, Pneumonia, Pseudomembranous colitis, Pyrexia, Rash, Seizure, Transaminases increased, Toxic epidermal necrolysis, Unstable angina, Swelling of face or tongue
Potentially Fatal: Anaphylaxis, severe dermatologic reactions.
Mechanism of Action
Oseltamivir is a prodrug of oseltamivir carboxylate (OC). OC is a potent selective competitive inhibitor of neuraminidase (an enzyme required for viral replication) of the influenza virus A and B. It prevents the release of viruses from infected host cell.