Azithromycin Eye Drops is indicated for the treatment of bacterial conjunctivitis caused by CDC coryneform group G, Haemophilus influenzae, Staphylococcus aureus, Streptococcus mitis group, and Streptococcus pneumoniae.

Azithromycin is stable in acidic conditions, allowing oral administration without the need for protection from gastric acid. It is efficiently absorbed, with better absorption when taken on an empty stomach. Peak plasma levels are typically achieved within 2.1 to 3.2 hours after oral dosing. Due to its accumulation in phagocytic cells, azithromycin is transported to infection sites, where it is released in high concentrations during active phagocytosis. Tissue concentrations may exceed plasma levels by more than 50 times, primarily due to ion trapping and its high lipid solubility.

The extended half-life of azithromycin permits once-daily dosing while maintaining bacteriostatic activity in infected tissues for several days. After a single 500 mg dose, plasma concentrations decline in a multiphasic manner, with an apparent clearance of approximately 630 mL/min and a terminal elimination half-life of about 68 hours. This prolonged half-life is attributed to extensive tissue uptake and gradual release. Azithromycin is mainly eliminated through biliary excretion in unchanged form, with about 6% of the administered dose excreted unchanged in urine over one week.

Microbiology: Azithromycin exerts its antibacterial action by binding to the 50S ribosomal subunit of susceptible microorganisms, thereby inhibiting protein synthesis without affecting nucleic acid synthesis. It has demonstrated activity against a broad spectrum of organisms both in vitro and in clinical settings, including:

• Aerobic and facultative gram-positive microorganisms: Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pneumoniae, Streptococcus pyogenes
• Aerobic and facultative gram-negative microorganisms: Haemophilus ducreyi, Haemophilus influenzae, Moraxella catarrhalis, Neisseria gonorrhoeae
• Other microorganisms: Chlamydia pneumoniae, Chlamydia trachomatis, Mycoplasma pneumoniae (β-lactamase production does not affect azithromycin activity)
• Additional gram-positive microorganisms: Streptococci (Groups C, F, G), Viridans group streptococci
• Additional gram-negative microorganisms: Bordetella pertussis, Legionella pneumophila
• Anaerobic microorganisms: Peptostreptococcus species, Prevotella bivia

Children of one year of age and adults: Instill 1 drop in affected eye(s) twice daily for the first 2 days then once daily for the next 5 days.

Pediatric Use: The safety and effectiveness of Azithromycin Eye Drops in pediatric patients below 1 year of age have not been established.

Children less than one year of age: Not recommended.

Drug interaction studies have not been conducted with Azithromycin Eye Drops.

Azithromycin Eye Drops is contraindicated in patients with hypersensitivity to any component of the preparation.

Reported side effects include eye irritation, contact dermatitis, corneal erosion, dry eye, punctate keratitis, and similar ocular reactions.

Azithromycin is classified as Pregnancy Category B. Animal studies have shown no evidence of harm to the fetus. However, there are no adequate and well-controlled studies in pregnant women. Since animal reproduction studies do not always predict human response, Azithromycin should be used during pregnancy only if clearly needed. It is not known whether Azithromycin is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Azithromycin is administered to a nursing woman.

Azithromycin Eye Drops is intended for topical ophthalmic use only. It should not be administered systemically, injected subconjunctivally, or introduced directly into the anterior chamber of the eye.

Macrolides

Store the unopened bottle under refrigeration at 2°C to 8°C. Once opened, the bottle may be stored at 25°C for up to 14 days. Discard the bottle 14 days after opening.