indication

For the treatment of bacterial infection caused by susceptible strains such as S. pneumoniae, H. influenzae, H. parainfluenzae, or M. catarrhalis, S. pneumoniae (including multi-drug resistant strains [MDRSP]), M. pneumoniae, C. pneumoniae, or K. pneumoniae.

pharmacology

Gemifloxacin is a quinolone/fluoroquinolone antibiotic. Gemifloxacin is bactericidal and its mode of action depends on blocking of bacterial DNA replication by binding itself to an enzyme called DNA gyrase, which allows the untwisting required to replicate one DNA double helix into two. Notably the drug has 100 times higher affinity for bacterial DNA gyrase than for mammalian. Gemifloxacin is a broad-spectrum antibiotic that is active against both Gram-positive and Gram-negative bacteria.

mechanism of action

The bactericidal action of gemifloxacin results from inhibition of the enzymes topoisomerase II (DNA gyrase) and topoisomerase IV, which are required for bacterial DNA replication, transcription, repair, and recombination.

biotransformation

Gemifloxacin is metabolized to a limited extent by the liver. All metabolites formed are minor (<10% of the administered oral dose); the principal ones are N-acetyl gemifloxacin, the E-isomer of gemifloxacin and the carbamyl glucuronide of gemifloxacin.

absorption

Rapidly absorbed from the gastrointestinal tract. The absolute bioavailability averages approximately 71%.

half life

7 (± 2) hours

route of elimination

Gemifloxacin and its metabolites are excreted via dual routes of excretion.Following oral administration of gemifloxacin to healthy subjects, a mean (± SD) of 61 ± 9.5% of the dose was excreted in the feces and 36 ± 9.3% in the urine as unchanged drug and metabolites. The mean (± SD) renal clearance following repeat doses of 320 mg was approximately 11.6 ± 3.9 L/hr (range 4.6-6 L/hr), which indicates active secretion is involved in the renal excretion of gemifloxacin.

drug interactions

Aluminium: Formation of non-absorbable complexes

Calcium Acetate: Calcium salts such as calcium acetate may decrease the absorption of quinolone antibiotics such as gemifloxacin. Of concern only with oral administration of both agents. Interactions can be minimized by administering oral quinolone at least 2 hours before, or 6 hours after, the dose of an oral calcium supplement. Monitor for decreased therapeutic effects of oral quinolones if administered with oral calcium supplements.

Iron: Formation of non-absorbable complexes

Iron Dextran: Formation of non-absorbable complexes

Magnesium: Formation of non-absorbable complexes

Magnesium oxide: Formation of non-absorbable complexes

Magnesium salicylate: Formation of non-absorbable complexes

Sucralfate: Formation of non-absorbable complexes

Zinc: Formation of non-absorbable complexes