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.