Adults

Typically 500 mg to 1 g intravenously every 8 hours, depending on the severity and type of infection. For meningitis, 1 g every 8 hours.

Elderly

No specific dosage adjustment needed for elderly patients with normal renal function. Dosage should be adjusted based on renal function.

Renal_impairment

Dosage reduction is required for patients with creatinine clearance less than 51 mL/min. For CrCl 26-50 mL/min, 500 mg every 12 hours. For CrCl 10-25 mL/min, 500 mg every 24 hours. For CrCl <10 mL/min, 500 mg every 24 hours (after dialysis on dialysis days).

Onset

Rapid onset of action, typically within minutes after IV infusion.

Excretion

Approximately 70% of the administered dose is excreted unchanged in the urine within 12 hours. Renal excretion is mainly via glomerular filtration and tubular secretion.

Half life

Approximately 1 hour in adults with normal renal function.

Absorption

Rapid and complete absorption after intravenous administration. Bioavailability is 100%.

Metabolism

Primarily metabolized by hydrolysis of the beta-lactam ring to an open-ring metabolite, which is microbiologically inactive. Not significantly metabolized by the liver.

Probenecid

Increases the plasma concentration and prolongs the half-life of meropenem by inhibiting its renal excretion. Co-administration is not recommended.

Valproic Acid

Concomitant use with meropenem may decrease valproic acid serum concentrations to subtherapeutic levels, leading to loss of seizure control. Avoid concomitant use; consider alternative antibiotics.

Oral Anticoagulants

Concomitant use with antibiotics, including carbapenems, may enhance the anticoagulant effects, increasing the risk of bleeding. Monitor INR.