gatifloxacin
Tequin

Available forms
Available by prescription only
Injection: 200 mg/20-ml vial, 400 mg/40-ml vial, 200 mg in 100 ml D₅W, 400 mg in 200 ml D₅W
Tablets: 200 mg, 400 mg

Indications and dosages
 Acute bacterial exacerbation of chronic bronchitis caused by Streptococcus pneumoniae, Haemophilus influenzae, H. parainfluenzae, Moraxella catarrhalis, or Staphylococcus aureus. Adults: 400 mg I.V. or P.O. daily for 5 days.
 Complicated urinary tract infection caused by Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis; acute pyelonephritis caused by E. coli. Adults: 400 mg I.V. or P.O. daily for 7 to 10 days.
 Acute sinusitis caused by S. pneumoniae or H. influenzae. Adults: 400 mg I.V. or P.O. daily for 10 days.
 Community-acquired pneumonia caused by S. pneumoniae, H. influenzae, H. parainfluenzae, M. catarrhalis, S. aureus, Mycoplasma pneumoniae, Chlamydia pneumoniae, or Legionella pneumophila. Adults: 400 mg I.V. or P.O. daily for 7 to 14 days.
 Uncomplicated urethral gonorrhea in men and cervical gonorrhea or acute uncomplicated rectal infections in women caused by Neisseria gonorrhoeae. Adults: 400 mg P.O. or I.V. as single dose.
 Uncomplicated urinary tract infection caused by E. coli, K. pneumoniae, or P. mirabilis. Adults: 400 mg I.V. or P.O. as single dose, or 200 mg I.V. or P.O. daily for 3 days.
≡ Dosage adjustment. For patients with creatinine clearance less than 40 ml/minute, those on hemodialysis, and those on continuous peritoneal dialysis, initial dose is 400 mg I.V. or P.O. daily, and subsequent doses are 200 mg I.V. or P.O. daily. For patients on hemodialysis, administer after hemodialysis session is complete.

Pharmacodynamics
Antibiotic action: Gatifloxacin inhibits DNA gyrase and topoisomerase, preventing cell replication and division. It is active against gram-positive and gram-negative organisms, including S. aureus, S. pneumoniae, E. coli, H. influenzae, H. parainfluenzae, K. pneumoniae, M. catarrhalis, N. gonorrhoeae, P. mirabilis, C. pneumoniae, L. pneumophila, and M. pneumoniae.

Pharmacokinetics
Absorption: 96% of gatifloxacin is absorbed after oral administration; levels peak in 1 to 2 hours.
Distribution: Gatifloxacin is 20% protein-bound. It’s widely distributed into many tissues and fluids.
Metabolism: Limited biotransformation.
Excretion: More than 70% of gatifloxacin is excreted unchanged by the kidneys. Serum half-life is 7 to 14 hours.

Contraindications and precautions
Contraindicated in patients hypersensitive to fluoroquinolones. Don’t use in patients with prolongation of QTc interval or in patients with uncorrected hypokalemia.
  Use cautiously in patients with clinically significant bradycardia, acute myocardial ischemia, known or suspected CNS disorders, or renal insufficiency.

Interactions
Drug-drug. Aluminum- or magnesium-based antacids: Decreases absorption of antibiotic. Give antibiotic 4 hours before antacid.
Antidiabetics (glyburide, insulin): May cause symptomatic hypoglycemia or hyperglycemia. Monitor blood glucose level.
Antipsychotics, erythromycin, tricyclic antidepressants: May prolong QTc interval. Use cautiously.
Class IA antiarrhythmics (procainamide, quinidine), class III antiarrhythmics (amiodarone, sotalol): May prolong QTc interval. Avoid use together.
Digoxin: May increase digoxin levels. Watch for signs of digoxin toxicity.
NSAIDs: Increases risk of CNS stimulation and seizures. Use together cautiously.
Probenecid: Increases gatifloxacin levels and prolongs half-life. Monitor patient closely.
Warfarin: May enhance effects of warfarin. Monitor PT and INR.
Drug-lifestyle. Sun exposure: Photosensitivity reactions may occur. Advise patient to take precautions.

Adverse reactions
CNS: headache, dizziness, abnormal dreams, insomnia, paresthesia, tremor, vertigo, fever.
CV: palpitations, chest pain, peripheral edema.
EENT: tinnitus, abnormal vision, pharyngitis.
GI: nausea, diarrhea, abdominal pain, constipation, dyspepsia, oral candidiasis, glossitis, stomatitis, mouth ulcer, vomiting, taste perversion.
GU: dysuria, hematuria, vaginitis.
Musculoskeletal: back pain.
Respiratory: dyspnea.
Skin: rash, redness at injection site, sweating.
Other: allergic reaction, chills.

Effects on lab test results
None reported.

Overdose and treatment
Signs and symptoms of overdose include decreased respiratory rate, vomiting, tremors, and convulsions.
 To treat an overdose of oral gatifloxacin, empty the stomach by inducing vomiting or performing gastric lavage. Provide symptomatic and supportive treatment, monitor ECG, and maintain hydration. Gatifloxacin isn’t removed by hemodialysis or peritoneal dialysis.

Special considerations
• In patients being treated for gonorrhea, test for syphilis at time of diagnosis.
• Dilute drug in single-use vials with D₅W or normal saline solution to a final concentration of 2 mg/ml before administration. Diluted solutions are stable for 14 days at room temperature or refrigerated. Frozen solutions are stable up to 6 months except for 5% sodium bicarbonate solutions. Thaw at room temperature. After thawing, solutions are stable for 14 days when stored at room temperature or under refrigeration. Don’t mix with other drugs. Infuse over 60 minutes.
• Discard any unused portion of the single dose vials.
• Pseudomembranous colitis may occur in patients taking antibiotics.
• Discontinue drug if patient experiences convulsions, increased intracranial pressure, psychosis, or CNS stimulation leading to tremors, restlessness, light-headedness, confusion, hallucinations, paranoia, depression, nightmares, and insomnia.
• Discontinue drug if patient experiences pain, inflammation, or rupture of a tendon.
• Discontinue drug for skin rash or other sign of hypersensitivity.
Breast-feeding patients
• It isn’t known whether gatifloxacin appears in breast milk. Use cautiously in breast-feeding women.
Pediatric patients
• Safety and effectiveness haven’t been established in patients younger than age 18.

Patient education
• Tell patient to take drug as prescribed and to finish all of it even if symptoms disappear.
• Advise patient to take drug 4 hours before products that contain aluminum, magnesium, zinc, or iron.
• Urge patient to use sunblock and wear protective clothing when exposed to excessive sunlight.
• Warn patient to avoid hazardous tasks until adverse CNS effects of drugs are known.
• Advise diabetic patient to monitor blood glucose levels and call if hypoglycemia occurs.
• Urge patient to immediately report symptoms of allergic reaction, such as palpitations, fainting spells, rash, hives, difficulty swallowing or breathing, tightness in throat, hoarseness, and swelling of the lips, tongue, or face.
• Advise patient to stop drug, refrain from exercise, and call if pain, inflammation, or rupture of a tendon occurs.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use