Oral Uncomplicated lower urinary tract infections Adult: 1 g 4 times daily for 1-2 wk. Long-term therapy: Reduce daily dose to 2 g. Child: >3 mth: 50 mg/kg daily in 4 equally divided doses. Long-term therapy: Reduce dose to 30 mg/kg daily. Prophylaxis: 15 mg/kg bid. Renal impairment: Reduced doses should be considered. Hepatic impairment:Reduced doses should be considered. Oral Shigellosis Adult: 1 g 4 times daily for 5 days. Child: ≥3 mth: 15 mg/kg 4 times daily for 5 days. Renal impairment: Reduced doses should be considered. Hepatic impairment: Reduced doses should be considered.
Hypersensitivity. History of convulsive disorders or porphyria.Infants <3 mth.Severe renal impairment.Hepatic or moderate renal impairment, severe cerebral arteriosclerosis, G6PD deficiency. Monitor blood counts, renal and hepatic function for treatment >2 wk. Children <18 yr. Elderly. Avoid exposure to sunlight or sunlamps. Pregnancy and lactation.
Absorption reduced by sucralfate, and divalent and trivalent cations e.g. aluminium, calcium, iron, magnesium, zinc. Excretion reduced and plasma concentrations increased with probenecid. Reduced effects with chloramphenicol, nitrofurantoin, tetracycline.
Potentially Fatal: Fatal haemorrhagic enterocolitis may occur when used with high-dose melphalan in children. Increased risk of nephrotoxicity with ciclosporin. May ↑effects of oral anticoagulants e.g. warfarin.
Absorption: Rapidly and almost completely absorbed from the GI tract. (oral); peak plasma concentrations after 1-2 hr (oral). Distribution: Crosses the placenta; enters the breast milk. Protein-binding: 93% (nalidixic acid); 63% (hydroxynalidixic acid). Metabolism: Partially converted in the liver to hydroxynalidixic acid. Excretion: Via urine (80-90% as inactive metabolites); faeces (4%); 1-2.5 hr (elimination half-life).