Adults

Usual adult dose is 1-2 gm administered once daily (every 24 hours) or in two divided doses (every 12 hours). In severe cases, the dose may be increased up to 4 gm daily.

Elderly

No dosage adjustment is generally required for elderly patients unless there is severe renal or hepatic impairment.

Renal_impairment

In patients with severe renal impairment (creatinine clearance <10 mL/min), a maximum daily dose of 2 gm should not be exceeded. Dosage adjustments may be needed in combined severe renal and hepatic dysfunction.

Onset

Rapid, typically within minutes for IV administration and 2-3 hours for peak plasma concentration after IM administration.

Excretion

Approximately 50-60% excreted via kidneys (glomerular filtration and tubular secretion) and 40-50% via bile and feces.

Half life

Approximately 6-9 hours; prolonged in neonates and patients with severe renal or hepatic impairment.

Absorption

Rapidly and completely absorbed after intramuscular (IM) administration; intravenous (IV) administration provides immediate systemic availability.

Metabolism

Partially metabolized in the liver to inactive metabolites. About 33-67% is excreted unchanged.

Aminoglycosides

Synergistic antibacterial effect, but increased risk of nephrotoxicity. Monitor renal function.

Oral contraceptives

May reduce the efficacy of oral contraceptives. Advise additional contraceptive methods.

Calcium-containing solutions

Concomitant use is contraindicated in neonates due to precipitation risks. In other age groups, a washout period is recommended if co-administration is unavoidable.

Oral anticoagulants (e.g., Warfarin)

Ceftriaxone may enhance the anticoagulant effect, increasing the risk of bleeding. Monitor INR/PT closely.