Tarivid Mechanism of Action

Microbiology: Tarivid (ofloxacin) is one of the fluorinated quinolones. It is an orally administered broad-spectrum antibacterial drug, active against most gram-negative bacteria, many gram-positive bacteria and some anaerobes.
The susceptible gram-negative bacteria include Citrobacter, Enterobacter, Klebsiella, Proteus, Salmonella and Shigella spp, Y. enterocolitica, E. coli, H. influenzae, N. gonorrhoeae, Providencia, Serratia and Pseudomonas spp, V. cholerae, L. pneumophila and C. jejuni. Against P. aeruginosa, it is as potent as gentamicin and several times more potent than cefotaxime.
The susceptible gram-positive bacteria include S. aureus, S. pneumoniae, S. faecalis and L. monocytogenes. Some anaerobic organisms, including B. melaninogenicus, B. fragilis and C. welchii, are moderately susceptible. Ofloxacin is also active against C. trachomatis and M. pneumoniae.
Like other quinolones, ofloxacin is bactericidal through inhibition of the A subunits of the enzyme DNA gyrase which controls supercoiling of DNA in bacteria. The antibacterial activity of ofloxacin is not influenced by the bacterial resistance to non-quinolone antibacterial drugs, but it is markedly reduced by reduction of pH or the presence of urine.
Pharmacokinetics: Oral administration of a single 300-mg dose of ofloxacin produces a peak serum concentration of about 3 mcg/mL within 2 hrs. A dosage of 300 mg twice daily for up to 14 days produces a peak serum level ranging from 3-6 mcg/mL on the last day. Food only delays absorption, while antacids may markedly reduce absorption. Compared to norfloxacin and ciprofloxacin at the same dose, ofloxacin is more rapidly absorbed and produces a higher serum level and 4 times higher AUC (AUC represents the amount of drug absorbed).
Ofloxacin is widely distributed to most tissues and body fluids. The volume of distribution is >1 L/kg and the tissue concentrations achieved are at least as high as the serum level for most tissues.
After single doses of 100-600 mg, 70-98% of ofloxacin is excreted unchanged in the urine within 48 hrs and the urinary concentration remains above the MIC₉₀ for most bacterial species at 48 hrs after administration. The elimination half-life after doses of 200 mg or more is about 6 hrs or more (up to 7.5 hrs). In patients with renal impairment, peak serum concentrations are delayed; the elimination half-life and AUC are substantially increased depending on the degree of renal impairment and thus dosage adjustments may be necessary.