The new
fluoroquinolones (
clinafloxacin,
gatifloxacin,
gemifloxacin,
grepafloxacin,
levofloxacin,
moxifloxacin,
sitafloxacin,
sparfloxacin and
trovafloxacin) offer excellent activity against Gram-negative bacilli and improved Gram-positive activity (e.g. against Streptococcus pneumoniae and Staphylococcus aureus) over
ciprofloxacin.
Ciprofloxacin still maintains the best in vitro activity against Pseudomonas aeruginosa.
Clinafloxacin,
gatifloxacin,
moxifloxacin,
sitafloxacin,
sparfloxacin and
trovafloxacin display improved activity against anaerobes (e.g. Bacteroides fragilis) versus
ciprofloxacin. All of the new
fluoroquinolones display excellent bioavailability and have longer serum half-lives than
ciprofloxacin allowing for once daily dose administration. Clinical trials comparing the new
fluoroquinolones to each other or to standard
therapy have demonstrated good efficacy in a variety of community-acquired
respiratory infections (e.g.
pneumonia, acute exacerbations of
chronic bronchitis and acute
sinusitis). Limited data suggest that the new
fluoroquinolones as a class may lead to better outcomes in community-acquired
pneumonia and acute exacerbations of
chronic bronchitis versus comparators. Several of these agents have either been withdrawn from the market, had their use severely restricted because of adverse effects (
clinafloxacin because of
phototoxicity and hypoglycaemia;
grepafloxacin because of prolongation of the QTc and resultant
torsades de pointes;
sparfloxacin because of
phototoxicity; and
trovafloxacin because of hepatotoxicity), or were discontinued during developmental phases. The remaining
fluoroquinolones such as
gatifloxacin,
gemifloxacin,
levofloxacin and
moxifloxacin have adverse effect profiles similar to
ciprofloxacin. Extensive post-marketing safety surveillance data (as are available with
ciprofloxacin and
levofloxacin) are required for all new
fluoroquinolones before safety can be definitively established. Drug interactions are limited; however, all
fluoroquinolones interact with
metal ion containing drugs (eg.
antacids). The new
fluoroquinolones (
gatifloxacin,
gemifloxacin,
levofloxacin and
moxifloxacin) offer several advantages over
ciprofloxacin and are emerging as important therapeutic agents in the treatment of community-acquired
respiratory infections. Their broad spectrum of activity which includes respiratory pathogens such as
penicillin and
macrolide resistant S. pneumoniae, favourable pharmacokinetic parameters, good bacteriological and clinical efficacy will lead to growing use of these agents in the treatment of community-acquired
pneumonia, acute exacerbations of
chronic bronchitis and acute
sinusitis. These agents may result in cost savings especially in situations where, because of their potent broad-spectrum activity and excellent bioavailability, they may be used orally in place of intravenous antibacterials. Prudent use of the new
fluoroquinolones will be required to minimise the development of resistance to these agents.