Adults

Oral: 250-500 mg every 6 hours (four times daily). For severe infections, dosage may be increased up to 1g every 6 hours. Administer 30-60 minutes before meals for optimal absorption.

Elderly

No specific dosage adjustment required unless there is significant renal impairment. Monitor renal function.

Renal_impairment

CrCl 10-50 mL/min: 250 mg every 8-12 hours. CrCl <10 mL/min: 250 mg every 12-24 hours. Severe impairment may require further reduction.

Onset

Rapid onset of action.

Excretion

Primarily excreted by the kidneys (renal excretion), with 65-80% of the dose recovered unchanged in the urine within 6 hours.

Half life

Approximately 0.5-1 hour in individuals with normal renal function.

Absorption

Well absorbed from the gastrointestinal tract, especially when taken on an empty stomach. Peak plasma concentrations are usually achieved within 1-2 hours after oral administration.

Metabolism

Partially metabolized in the liver to inactive metabolites. About 10-20% undergoes metabolic conversion.

Warfarin

Concurrent use may alter the international normalized ratio (INR), requiring close monitoring and possible dose adjustment of warfarin.

Probenecid

May increase and prolong flucloxacillin plasma concentrations by reducing its renal tubular secretion.

Methotrexate

Flucloxacillin may reduce renal excretion of methotrexate, potentially increasing its toxicity.

Oral Contraceptives

May rarely reduce the efficacy of oral contraceptives; advise additional non-hormonal contraception.