Adults

Typically, 400 mg once daily or 200 mg every 12 hours. For 100 mg/5 ml suspension, this would be 40 ml (400 mg) once daily or 20 ml (200 mg) every 12 hours.

Elderly

No specific dosage adjustment solely based on age is typically required, but renal function should be assessed and dose adjusted if needed.

Renal_impairment

Creatinine clearance 21-60 mL/min: 300 mg daily. Creatinine clearance < 20 mL/min: 200 mg daily.

Onset

Not precisely defined, but antibacterial effect starts relatively quickly after administration.

Excretion

Primarily excreted by the kidneys (50-60% as unchanged drug in urine).

Half life

3 to 4 hours.

Absorption

Approximately 40-50% orally absorbed. Food slows absorption but does not affect the extent.

Metabolism

Not extensively metabolized; about 10% converted to inactive metabolites.

Warfarin

May increase anticoagulant effect (increased INR), requiring close monitoring.

Carbamazepine

May increase carbamazepine plasma concentrations, requiring monitoring.

Oral Contraceptives

Potential for reduced efficacy of oral contraceptives (rare), advise additional contraception.