Pharmacology: Bactericidal; fluoroquinolones act intracellularly by inhibiting topoisomerase II (DNA gyrase) and/or topoisomerase IV. Topoisomerases are essential bacterial enzymes that are critical catalysts in the duplication, transcription, and repair of bacterial DNA.
Pharmacokinetics: Distribution: Fluoroquinolones are widely distributed to most body fluids and tissues; high concentrations are attained in the kidneys, gallbladder, liver, lungs, gynecologic tissue, prostatic tissue, phagocytic cells, urine, sputum, and bile. Ciprofloxacin is also distributed to skin, fat, muscle, bone, and cartilage. Ciprofloxacin has been found to penetrate into the cerebrospinal fluid (CSF). CSF concentrations of ciprofloxacin reach 10% of the peak serum concentration with noninflamed meninges, and 30% to 50% with inflamed meninges.
Half-life (hr): Normal renal function: 4; Impaired renal function- 6-8.
Time to peak serum concentration: 1-2 hr.
Peak serum concentration after dose: 1.2-1.4 mcg/mL; Dose: 250 mg, 2.4-4.3 mcg/mL; Dose: 500 mg, 3.4-4.3 mcg/mL; Dose: 750 mg, 5.4 mcg/mL; Dose: 1000 mg.
Peak urine concentration after dose: >200 mcg/mL; Dose: 250 mg.
Protein binding: 20-40%.
Renal excretion (% unchanged/hrs): 40-50/24.
Biliary excretion: 20-35%. VolD: 2 liter/Kg.
Removal by dialysis: HD - <10%; PD - <10%.