oseltamivir

CLINICAL USE

Treatment and post-exposure prevention of influenza

DOSE IN NORMAL RENAL FUNCTION

Treatment: 75 mg twice daily for 5 days Post-exposure prevention: 75 mg once daily for at least 10 days; up to 6 weeks if epidemic in community

PHARMACOKINETICS

Molecular weight :410.4 (as phosphate)

%Protein binding :42 (3 as carboxylate)

%Excreted unchanged in urine : Negligible (99% excreted as carboxylate metabolite in urine)

Volume of distribution (L/kg) :0.3–0.4

half-life – normal/ESRD (hrs) :1–3, (6–10 as metabolite)/ >20

DOSE IN RENAL IMPAIRMENT

GFR (mL/MIN)

30–50 Dose as in normal renal function10–30 Treatment: 75 mg once daily or 30 mg twice daily Prophylaxis: 75 mg every 48 hours or 30 mg once daily

<10 : Treatment: 30 mg once off dose Prophylaxis: 30 mg every 10 days1 See ‘Other Information’

DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

CAPD :Dialysed. Treatment: 30 mg stat; prophylaxis: 30 mg weekly2

HD :Dialysed. Treatment: 30 mg stat; prophylaxis: 30 mg after alternate dialysis sessions2

HDF/high flux :Dialysed. Treatment: 30 mg stat; prophylaxis: 30 mg after alternate dialysis sessions2

CAV/VVHD :Unknown dialysability. Dose as in GFR=10–30 mL/min

IMPORTANT DRUG INTERACTIONS

Potentially hazardous interactions with other drugs

None known

ADMINISTRATION

Reconstition

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Route

Oral

Rate of Administration

–

Comments

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OTHER INFORMATION

Oseltamivir is a prodrug; extensively metabolised in the liver to the active carboxylate metaboliteAt least 75% of the oral dose reaches the systemic circulation as the carboxylateAll the active metabolite is excreted in the urineA lower dose is required in severe renal disease due to the active metabolite accumulating

See how to identify renal failure stages according to GFR calculation

See how to diagnose irreversible renal disease

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