Erythromycin Ophthalmic Ointment belongs to the macrolide group of antibiotics. It is basic and readily forms a salt when combined with an acid. The base, as crystals or powder, is slightly soluble in water, moderately soluble in ether, and readily soluble in alcohol or chloroform. Erythromycin ((3R*, 4S*, 5S*, 6R*, 7R*, 9R*, 11R*, 12R*, 13S*, 14R*)-4-[(2,6-dideoxy-3-C-methyl-3-O-methyl-α-L-ribo-hexopyranosyl)-oxy]-14-ethyl-7,12,13-trihy-droxy-3,5,7,9,11,13-hexamethyl-6-[[3,4,6-trideoxy-3-(dimethyl-amino)-β-D-xylo-hexopyranosyl]oxy]oxacy-clotetradecane-2,10-dione)) is an antibiotic produced from a strain of Streptomyces erythraeus.

It has the following structural formula:

Each gram contains Erythromycin USP 5 mg in a sterile ophthalmic base of mineral oil and white petrolatum.

Microbiology: Erythromycin inhibits protein synthesis without affecting nucleic acid synthesis. Erythromycin is usually active against the following organisms in vitro and in clinical infections:

•   Streptococcus pyogenes (group A β-hemolytic)
•   Alpha-hemolytic streptococci (viridans group)
•   Staphylococcus aureus, including penicillinase-producing strains (methicillin-resistant staphylococci are uniformly resistant to erythromycin)
•   Streptococcus pneumoniae
•   Mycoplasma pneumoniae (Eaton Agent, PPLO)
•   Haemophilus influenzae (not all strains of this organism are susceptible at the erythromycin concentrations ordinarily achieved)
•   Treponema pallidum
•   Corynebacterium diphtheriae
•   Neisseria gonorrhoeae
•   Chlamydia trachomatis

For the treatment of superficial ocular infections involving the conjunctiva and/or cornea caused by organisms susceptible to erythromycin.

For prophylaxis of ophthalmia neonatorum due to N. gonorrhoeae or C. trachomatis.

The effectiveness of erythromycin in the prevention of ophthalmia caused by penicillinase-producing N.gonorrhoeae is not established.

For infants born to mothers with clinically apparent gonorrhea, intravenous or intramuscular injections of aqueous crystalline penicillin G should be given; a single dose of 50,000 units for term infants or 20,000 units for infants of low birth weight. Topical prophylaxis alone is inadequate for these infants.

This drug is contraindicated in patients with a history of hypersensitivity to erythromycin.

General: The use of antimicrobial agents may be associated with the overgrowth of nonsusceptible organisms including fungi; in such a case, antibiotic administration should be stopped and appropriate measures taken.

The most frequently reported adverse reactions are minor ocular irritations, redness, and hypersensitivity reactions.

In the treatment of superficial ocular infections, a ribbon approximately 1 cm in length of Erythromycin Opthalmic Ointment should be applied directly to the infected structure up to 6 times daily, depending on the severity of the infection.

For prophylaxis of neonatal gonococcal or chlamydial conjunctivitis, a ribbon of ointment approximately 1 cm in length should be instilled into each lower conjunctival sac. The ointment should not be flushed from the eye following instillation. A new tube should be used for each infant.

Sterile Erythromycin Ophthalmic Ointment USP, 0.5% is available as follows:

3.5 g (1/8 oz) sterile tamper-resistant tube

(NDC 17478-824-35)

Carton of fifty (50) Unit Dose 1 g tube

(NDC 17478-824-01)