Adults

Usual dose is 1 gm intravenously or intramuscularly every 8-12 hours. For severe infections, dosage may be increased to 2 gm every 8 hours, or up to 12 gm/day in divided doses.

Elderly

Dosage adjustment may be necessary in elderly patients with impaired renal function. Monitor renal function.

Renal_impairment

For creatinine clearance <20 mL/min, reduce maintenance dose by half. For creatinine clearance <5 mL/min, give 0.5-1 gm every 12-24 hours. Hemodialysis patients require an additional dose after dialysis.

Onset

Rapid, typically within minutes of IV administration.

Excretion

Primarily excreted by the kidneys (approximately 80% as unchanged drug and its metabolites within 24 hours), both by glomerular filtration and tubular secretion.

Half life

Approximately 1 hour for cefotaxime and 1.5 hours for its active metabolite, desacetylcefotaxime, in adults with normal renal function.

Absorption

Administered intravenously or intramuscularly, resulting in 100% bioavailability. Peak plasma concentrations are achieved rapidly after IV administration (within minutes) and within 30 minutes after IM administration.

Metabolism

Partially metabolized in the liver to its primary active metabolite, desacetylcefotaxime, which also possesses antimicrobial activity.

Probenecid

May decrease the renal tubular secretion of cefotaxime, leading to increased and prolonged plasma concentrations.

Loop Diuretics

Concurrent use with potent loop diuretics (e.g., Furosemide) may increase the risk of nephrotoxicity.

Aminoglycosides

Concurrent use may increase the risk of nephrotoxicity. Monitor renal function closely.

Oral Anticoagulants

May potentiate the anticoagulant effect in some cases. Monitor INR/PT.