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.

Side 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.

Mode 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.