Effect of several antimicrobial agents on ciprofloxacin uptake by human neutrophils. 
The effect of antimicrobial agent active against anaerobes, gram-positive cocci and fungi on the uptake of ciprofloxacin by human neutrophils (PMNs) was evaluated.  In the presence of therapeutic extracellular concentrations of these agents, ciprofloxacin reached high intracellular concentrations [cellular-to-extracellular ratio (C/E) greater than or equal to 2.9], this value being higher in the presence of amphotericin B (C/E 6.3 +/- 0.9).  The intracellular penetration of ciprofloxacin was higher when PMNs were stimulated with opsonized zymosan (C/E greater than or equal to 5.6).  In summary, none of the antimicrobial agents tested significantly impaired the uptake of ciprofloxacin by human PMNs.