Ciprofloxacin  (PDF Version)


Antibiotic Class:



Antimicrobial Spectrum:

Gram-positive:  methicillin-susceptible Staphylococcus aureus (MSSA) (lowest quinolone activity vs. MSSA), Streptococcus pneumoniae

Gram-negative:  Enterobacteriaceae, H. influenzae, other Haemophilus spp., N. gonorrhoeae, N. meningitides, M. catarrhalis, P. aeruginosa, S. maltophilia

Atypicals:  Legionella pneumophilia


Mechanism of Action:

Inhibition of topoisomerase (DNA gyrase) enzymes, which inhibits relaxation of supercoiled DNA and promotes breakage of double stranded DNA.



Fluoroquinolones produce both concentration-dependent  (peak:MIC), and a combination of concentration and time-dependent killing (AUC:MIC).



Dose of 750mg; Cmax: 3.5mg/ml; Volume of distribution: 3.2 L/kg; Table 2  & Table 3


Adverse Effects:

CNS:  headache, insomnia, dizziness; hallucinations, depression, psychotic reactions (rare)

Connective tissue:  tendon injury

Renal: interstitial nephritis

Cardiovascular: QTC prolongation, torsades de pointes, arrhythmias



Tablets: 100mg, 250mg, 500mg, 750mg, 500mg extended release tabs, 1000mg extended release   tablets

IV: 200mg, 400mg

Suspension: 250mg/5ml and 500mg/5ml (both in 100ml bottles)


Adult patients:

Lower respiratory tract infections: 500-750mg PO q12h / 400mg q8-12h IV x 7-14 days

Acute sinusitis: 500mg PO q12h / 400mg q12h IV x 10 days

Nosocomial pneumonia: 400mg IV q8h x 10-14 days

Uncomplicated UTI: 250mg PO q12h x 3 days

                                 500mg extended release tablets q24h

Complicated UTI/Pyelonephritis: 500mg PO q12h / 400mg IV q12h x 7-14 days

                                                      1000mg extended release tablets q24h

Prostatits: 500mg PO q12h / 400mg IV q12h x 28 days

Uncomplicated gonococcal infections: 500mg PO x 1 dose

Chancroid: 500mg PO q12h x 3 doses

Uncomplicated skin/skin structure: 500-750mg PO q12h x 7-14 days / 400mg IV q8-12h

Intra-abdominal infections: 500mg PO q12h x 7-14days / 400mg IV q12h

Infectious diarrhea: 500mg q12h x 3-5 days (current recommendations)

                                500mg PO q12h x 5-7 days (labeled)

Inhalational anthrax (post-exposure): 500mg PO q12h x 60 days

Febrile neutropenia: 400mg IV q8h



Complicated UTI/Pyelonephritis: 6-10mg/kg not to exceed 400mg per dose q8h x 10-21 days

                                                       10-20mg/kg not to exceed 750mg per dose q12h x 10-21 days

Inhalational anthrax (post-exposure): 10mg/kg not to exceed 400mg per dose q12h x 60 days

                                                            15mg/kg not to exceed 500mg per dose q12h x 60 days

Table 4


Disease state based dosing:

Renal failure:     IV: CrCl 30 mL/min or greater, give usual dose; CrCl 5-29 mL/min, 200-400 mg IV every 18-24 hr

                        ORAL: CrCl greater than 50 mL/min, give usual dose; CrCl 30-50 mL/min, 250-500 mg every 12 hr; CrCl 5-29 mL/min, 250-500 mg every 18 hr

Hepatic failure:  No dosing changes recommended at this time.


Dosing during Continuous Renal Replacement Therapy

CVVH (Continuous venovenous hemofiltration): 200mg IV q12h

CVVHD (Continuous venovenous hemodialysis): 200-40mg IVq12h

CVVHDF (Continuous venovenous hemodiafiltration) 200-400mg g IV q12h

Note: CVVH is mainly for fluid removal alone. Many institutions will employ more CVVHD or CVVHDF which combine dialysis with fluid removal.





Drug Interactions:

Anticoagulants:  Warfarin (prolonged warfarin half-life)

Divalent cations:  aluminum, magnesium zinc, iron, calcium, antacids, sucralfate reduced bioavailability of quinolones (potential to cause therapeutic failure)

Theophylline, caffeine, xanthines: clearance of these is inhibited with fluoroquinolones



Category C: Risk unknown. Human studies inadequate


Monitoring Requirements:

Therapeutic:  Culture and sensitivities, signs and symptoms of infection

Toxic:  Urinalysis, BUN, SCr, AST and ALT, physicial examination: encephalopathic changes


Brand names/Manufacturer:

Available by many names and manufacturers (click here)