Quinolone: Nalidixic acid
– Gram-negative bacteria
Was particularly useful against urinary tract infections prior to widespread resistance.
– Inhibits DNA replication via inhibition of topoisomerase type II (aka, gyrase) in Gram-negative bacteria
– Nausea and vomiting
– Visual changes
– Headache
– Rash
Fluoroquinolones: Ciprofloxacin, Levofloxacin, and Moxifloxacin
– Gram-negative infections of the urinary and gastrointestinal tracts.
– Moxifloxacin has activity against some Gram-positive bacteria and anaerobes, and is used to treat respiratory infections caused by
Haemophilus influenzae and
Streptococcus pneumoniae.
– Halt DNA replication by inhibiting topoisomerase type II (in Gram-negative bacteria) or topoisomerase type IV (in Gram-positive bacteria)
– Modification of these enzymes
– Increases in efflux pumps
– Gastrointestinal upset
– Rash
– Headache
–
QT prolongation
– Tendinopathy or rupture can occur
– Colitis
– They should not be taken with antacids, or during pregnancy.
– They should not be administered to children, due to the possibility of cartilage or bone tissue erosion.
Metronidazole
– Anaerobes
Helicobacter pylori
Gardnerella vaginalis
Clostridium difficile
– Also used to treat some parasitic infections
– Produces free radical metabolites that damage bacterial DNA
– Gastrointestinal upset
– Metallic taste
– Disulfiram-like reaction when combined with alcohol
Rifamycins: Rifampin and Rifabutin
– Mycobacteria
– Rfabutin is particularly active against [Myocbacterium avium
– Inhibit bacterial RNA synthesis
– Resistance appears more likely to develop with monotherapy
– Reddish-brown hue to the urine, saliva, tears, and other bodily fluids.
– Gastrointestinal upset
– Rash
– Headache
