17/01/2021
Drug Combination Studies
Two or more antimicrobial agents may be used simultaneously in therapy of a patient to treat more than one
infecting pathogen, to enhance killing of a pathogen, or to
suppress emergence of bacterial resistance. Numerous studies have evaluated the effects of combinations of quinolones
with other agents. In most of these studies, effects were
quantitated by measurement of fractional inhibitory concentration values, fractional bactericidal concentration values,
or effects on killing in time-kill curve studies, with interactions categorized as synergistic, indifferent or additive, or
antagonistic.
Against gram-negative bacteria, combination with a ,B_lactam drug, including ampicillin, carbenicillin, azlocillin,
mezlocillin, piperacillin, ceftazidime, cefotaxime, cefotetan,
ceftizoxime, cefsulodin, cefoperazone, moxalactam, imipenem, or aztreonam, or with an aminoglycoside, including
amikacin, gentamicin, or tobramycin, usually resulted in
effects that were indifferent or additive, occasionally synergistic, and notably only rarely antagonistic for norfloxacin
(485, 487, 537, 779), ciprofloxacin (81, 88, 99, 103, 106, 146,
275, 3'2, 507, 508, 779), ofloxacin (435, 779), pefloxacin (156,
481, 799), and enoxacin (24, 100, 796). In some studies with
P. aeruginosa, synergy was documented more frequently,
occurring in 54% of isolates treated with norfloxacin and
imipenem (485), 30, 50, and 56% treated with ciprofloxacin
and azlocillin (99, 507, 508), and 36 and 42% treated with
ciprofloxacin and imipenem (81, 275). In other studies with
P. aeruginosa, however, synergy was uncommon (103, 146,
322, 779), and the combination of ciprofloxacin and rifampin
was indifferent (424). Ciprofloxacin with fosfomycin was
synergistic against 60% of P. aeruginosa (222). For Cam pylobacterpylori, bismuth subcitrate was indifferent (75% of
strains) or synergistic (25%) in combination with ofloxacin
and indifferent with norfloxacin (794).
