Gatifloxacin
Common Brand Names: Tequin
Therapeutic Class: Fluoroquinolone antibiotic
Common Injectable Dosage Forms:
Solution for Injection: 200 mg/20 mL and 400 mg/40 mL vials
Dosage Ranges:
Acute bacterial exacerbation of chronic bronchitis due to Streptococcus pneumoniae, Haemophilus influenzae, Haemophilus parainfluenzae, Moraxella catarrhalis, or Staphylococcus aureus: 400 mg/day for 5 days.
Acute sinusitis caused by S. pneumoniae or H. influenzae: 400 mg/day for 10 days.
Community-acquired pneumonia caused by S. pneumoniae (including multi-drug resistant strains), H. influenzae, H. parainfluenzae, M. catarrhalis, S. aureus, Mycoplasma pneumoniae, Chlamydia pneumoniae, or Legionella pneumophila: 400 mg/day for 7-14 days.
Dosage in patients with impaired renal function: If Ccr is <40 mL/minute, give a 400 mg dose initially, followed by 200 mg IV every 24 hours. No adjustment necessary in hepatic impairment.
Administration and Stability: Must be diluted to concentration of 2 mg/mL and administered over 60 minutes. May be diluted with D5W, NS, D5NS, or D5LR. Do not dilute with SWFI (Sterile Water for Injection). Following dilution, solution is stable for 14 days when refrigerated. pH 3.5
Pharmacology/Pharmacokinetics: Gatifloxacin is a DNA gyrase inhibitor. DNA gyrase is an essential bacterial enzyme that maintains the structure of DNA and is required for DNA replication and transcription, DNA repair, and combination of DNA. DNA gyrase inhibition is bactericidal. Gatifloxacin has a wide range of activity against gram-negative and gram-positive bacteria, including H. influenzae, M. catarrhalis, S. pneumoniae, S. aureus, H. parainfluenzae, E. coli, N. gonorrhoeae, M. pneumoniae, L. pneumophila, and C. pneumoniae. Elimination half-life of gatifloxacin is 7-14 hours (longer in renal impairment) and bioavailability is approximately 96%. About 70% of drug is excreted unchanged in the urine.
Drug and Lab Interactions: May increase the effects of hypoglycemic agents and warfarin. Concomitant use with QT prolonging drugs (antiarrhythmics, erythromycin, cyclic antidepressants, etc.) may result in arrhythmias. Probenecid may increase gatifloxacin levels. Concomitant use with NSAIDs may rarely increase risk of seizure.
Contraindications/Precautions: Contraindicated in patients with a hypersensitivity to quinolones and in patients with diabetes mellitus. Use with caution in patients with bradycardia or acute myocardial ischemia. May prolong QT interval. Use caution in patients with hypokalemia. Discontinue in patients who experience CNS adverse effects. Safety and efficacy have not been established in those <18 years old. Pregnancy Category C.
Monitoring Parameters: WBC, s/s infection, s/s hypo/hyperglycemia
Adverse Effects: Headache, dizziness, nausea, diarrhea are more common effects. More serious, but rare, effects include Stevens-Johnson syndrome, seizures, severe hypoglycemia or hyperglycemia, tachycardia, and torsade de pointes.
Common Clinical Applications: Headache, dizziness, nausea, diarrhea are more common effects. More serious, but rare, effects include Stevens-Johnson syndrome, seizures, severe hypoglycemia or hyperglycemia, tachycardia, and torsade de pointes.