Focus on oral ciprofloxacin; clinical and economic considerations

Ciprofloxacin, a recently released oral fluorinated quinolone structurally related to nalidixic acid, joins norfloxacin as the second drug of this class to be released. Ciprofloxacin has a wide spectrum of antimicrobial activity and importantly demonstrates little cross resistance to non-quinolone drug classes (e.g. ureidopenicillins, cephalosporins, monobactams, carbapenems, aminoglycosides). Unlike other antibacterial classes such as the beta-lactams or aminoglycosides, ciprofloxacin does not suffer from transferable plasmid-mediated (i.e. R-factor) antibiotic resistance. Against gram-positive (including penicillin-resistant and methicillin-resistant staphylococci aureus) and gram-negative aerobic bacteria including Pseudomonas aeruginosa, ciprofloxacin demonstrates excellent activity. Ciprofloxacin is inactive against Trichomonas sp., treponemes, and fungi and anaerobes are considered resistant. Ciprofloxacin is rapidly absorbed from the gastrointestinal tract (i.e. 70-80% bioavailable), demonstrates extensive extravascular distribution, and its 3.5-5 hour half-life allows twice daily dosing. The bacteriologic and clinical efficacy of oral ciprofloxacin was shown to be comparable to third generation cephalosporins or aminoglycosides for osteomyelitis, cefotaxime for skin structure infections, and to a combination of tobramycin with azlocillin for pulmonary exacerbation of cystic fibrosis. Adverse events associated with ciprofloxacin are related mostly to gastrointestinal disturbance and consist of nausea/vomiting or diarrhea. Concomitant administration of ciprofloxacin and theophylline may lead to decreased theophylline clearance and necessitates periodic measurements of theophylline levels to avoid toxic levels. Treatment with oral ciprofloxacin should offer substantial cost savings over a variety of parenteral antimicrobial regimens (e.g. aminoglycoside + beta-lactams) for difficult to treat infections such as chronic pyelonephritis, osteomyelitis, and skin structure infections. Consideration of important precautions (e.g. contraindications, drug interactions) and potential disadvantages (e.g. emergence of resistance) must also guide the rational use of oral ciprofloxacin.