Gatifloxacin ophthalmic solution, 0.5% is indicated for the treatment of bacterial conjunctivitis caused by susceptible strains of the following organisms:

Aerobic Gram-Positive Bacteria:

Staphylococcus aureus

Staphylococcus epidermidis

Streptococcus mitis group*

Streptococcus oralis*

Streptococcus pneumoniae

Aerobic Gram-Negative Bacteria:

Haemophilus influenzae

*Efficacy for this organism was studied in fewer than 10 infections.

Patients 1 year of age or older: Instill one drop every two hours in the affected eye(s) while awake, up to 8 times on Day 1. Instill one drop two to four times daily in the affected eye(s) while awake on Days 2 through 7.

Five (5) mL bottle containing 2.5 mL of a 0.5% sterile topical ophthalmic solution.

None

5.1 Topical Ophthalmic Use Only

Gatifloxacin ophthalmic solution, 0.5% should not be introduced directly into the anterior chamber of the eye.

5.2 Growth of Resistant Organisms with Prolonged Use

As with other anti-infectives, prolonged use of gatifloxacin ophthalmic solution, 0.5% may result in overgrowth of nonsusceptible organisms, including fungi. If superinfection occurs, discontinue use and institute alternative therapy. Whenever clinical judgment dictates, the patient should be examined with the aid of magnification, such as slit lamp biomicroscopy and where appropriate, fluoroscein staining.

5.3 Avoidance of Contact Lens Wear

Patients should be advised not to wear contact lenses if they have signs and symptoms of bacterial conjunctivitis or during the course of therapy with gatifloxacin ophthalmic solution, 0.5% (see PATIENT COUNSELING INFORMATION, 17.2).

6.1 Clinical Studies Experience

Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice.

In clinical studies with gatifloxacin ophthalmic solution, 0.5% the most frequently reported adverse reactions occurring in ≥ 1 % of patients in the gatifloxacin study population (N=717) were: worsening of the conjunctivitis, eye irritation, dysgeusia, and eye pain.

Additional adverse events reported with other formulations of gatifloxacin ophthalmic solution include chemosis, conjunctival hemorrhage, dry eye, eye discharge, eyelid edema, headache, increased lacrimation, keratitis, papillary conjunctivitis, and reduced visual acuity.

Specific drug interaction studies have not been conducted with gatifloxacin ophthalmic solution, 0.5%.

8.1 Pregnancy

Pregnancy Category C

Teratogenic Effects: There were no teratogenic effects observed in rats or rabbits following oral gatifloxacin doses up to 50 mg/kg/day (approximately 1000-fold higher than the maximum recommended ophthalmic dose). However, skeletal/craniofacial malformations or delayed ossification, atrial enlargement, and reduced fetal weight were observed in fetuses from rats given ≥150 mg/kg/day (approximately 3000-fold higher than the maximum recommended ophthalmic dose). In a perinatal/postnatal study, increased late post-implantation loss and neonatal/perinatal mortalities were observed at 200 mg/kg/day (approximately 4000-fold higher than the maximum recommended ophthalmic dose).

Because there are no adequate and well-controlled studies in pregnant women, gatifloxacin ophthalmic solution, 0.5% should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

8.3 Nursing Mothers

Gatifloxacin is excreted in the breast milk of rats. It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when gatifloxacin ophthalmic solution, 0.5% is administered to a nursing woman.

8.4 Pediatric Use

The safety and effectiveness of gatifloxacin ophthalmic solution, 0.5% in infants below one year of age have not been established. Gatifloxacin ophthalmic solution, 0.5% has been demonstrated in clinical trials to be safe and effective for the treatment of bacterial conjunctivitis in pediatric patients one year or older (see CLINICAL STUDIES, 14).

8.5 Geriatric Use

No overall differences in safety or effectiveness have been observed between elderly and younger patients.

12.1 Mechanism of Action

Gatifloxacin is a fluoroquinolone antibacterial (see CLINICAL PHARMACOLOGY, 12.4).

12.3 Pharmacokinetics

Gatifloxacin ophthalmic solution 0.3% or 0.5% was administered to one eye of 6 healthy male subjects each in an escalated dosing regimen starting with a single 2 drop dose, then 2 drops 4 times daily for 7 days, and finally 2 drops 8 times daily for 3 days. At all time points, serum gatifloxacin levels were below the lower limit of quantification (5 ng/mL) in all subjects.

12.4 Microbiology

Gatifloxacin is an 8-methoxyfluoroquinolone with a 3-methylpiperazinyl substituent at C7. The antibacterial action of gatifloxacin results from inhibition of DNA gyrase and topoisomerase IV. DNA gyrase is an essential enzyme that is involved in the replication, transcription, and repair of bacterial DNA. Topoisomerase IV is an enzyme known to play a key role in the partitioning of the chromosomal DNA during bacterial cell division. The mechanism of action of fluoroquinolones including gatifloxacin is different from that of aminoglycoside, macrolide, and tetracycline antibiotics. Therefore, gatifloxacin may be active against pathogens that are resistant to these antibiotics and these antibiotics may be active against pathogens that are resistant to gatifloxacin. There is no cross-resistance between gatifloxacin and the aforementioned classes of antibiotics. Cross resistance has been observed between systemic gatifloxacin and some other fluoroquinolones.

Resistance to gatifloxacin in vitro develops via multiple-step mutations. Resistance to gatifloxacin in vitro occurs at a general frequency of 1 x 10-7 to 10-10.

Gatifloxacin has been shown to be active against most isolates of the following organisms both microbiologically and clinically, in conjunctival infections as described in the INDICATIONS AND USAGE, Section 1.

Aerobic Gram-Positive Bacteria:

Staphylococcus aureus

Staphylococcus epidermidis

Streptococcus mitis group*

Streptococcus oralis*

Streptococcus pneumoniae

Aerobic Gram-Negative Bacteria:

Haemophilus influenzae

*Efficacy for this organism was studied in fewer than 10 infections.

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

There was no increase in neoplasms among B6C3F1 mice given gatifloxacin in the diet for 18 months at doses averaging 81 mg/kg/day in males and 90 mg/kg/day in females. These doses are approximately 1600-fold and 1800-fold higher, respectively, than the maximum recommended ophthalmic dose of 0.05 mg/kg/day in a 50 kg human.

There was no increase in neoplasms among Fischer 344 rats given gatifloxacin in the diet for 2 years at doses averaging 47 mg/kg/day in males and 139 mg/kg/day in females (900- and 2800-fold higher, respectively, than the maximum recommended ophthalmic dose). A statistically significant increase in the incidence of large granular lymphocyte (LGL) leukemia was seen in males treated with a high dose of approximately 2000-fold higher than the maximum recommended ophthalmic dose. Fischer 344 rats have a high spontaneous background rate of LGL leukemia and the incidence in high-dose males only slightly exceeded the historical control range established for this strain.

In genetic toxicity tests, gatifloxacin was positive in 1 of 5 strains used in bacterial reverse mutation assays: Salmonella strain TA102. Gatifloxacin was positive in in vitro mammalian cell mutation and chromosome aberration assays. Gatifloxacin was positive in in vitro unscheduled DNA synthesis in rat hepatocytes but not human leukocytes. Gatifloxacin was negative in in vivo micronucleus tests in mice, cytogenetics test in rats, and DNA repair test in rats. The findings may be due to the inhibitory effects of high concentrations on eukaryotic type II DNA topoisomerase.

There were no adverse effects on fertility or reproduction in rats given gatifloxacin orally at doses up to 200 mg/kg/day (approximately 4000-fold higher than the maximum recommended ophthalmic dose for gatifloxacin ophthalmic solution, 0.5%).

17.1 Avoiding Contamination of the Product

Patients should be instructed to avoid contaminating the applicator tip with material from the eye, fingers, or other source.

17.2 Avoidance of Contact Lens Wear

Patients should be advised not to wear contact lenses if they have signs and symptoms of bacterial conjunctivitis.