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Polysporin offers inexpensive, effective anti-infective treatment
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Polysporin ointment (polymyxin B sulfate/bacitracin zinc, Glaxo Wellcome) is a broad-spectrum antibiotic that has been used for many years, causing few reactions while providing excellent therapeutic results. The antibiotic ointment has been my choice for treating the most common infection we encounter in optometric practice: blepharitis. Eyelid disease associated with Staphylococcus infection is a commonplace occurrence that requires maintenance treatment as the disease waxes and wanes throughout the patient’s lifetime.
Polysporin is also used for additional broad-spectrum coverage when treating more serious anterior surface infections. An inexpensive antibiotic such as Polysporin is an excellent choice to cover not only gram-positive organisms, but gram-negative bacteria as well.
Polysporin is supplied in a 3.5-g (0.125 oz.) ophthalmic tip tube dispenser. The ointment contains no preservatives. It is manufactured by Glaxo Wellcome in ophthalmic form and in an over-the-counter preparation for cuts and abrasions. Generic forms of bacitracin/polymyxin B are also available. Bacitracin contains 500 units of bacitracin zinc per gram of ointment. It is produced by growing the Bacillus subtilis species. Polymyxin B contains 10,000 units of polymyxin B sulfate per gram and is produced by growing Bacillus polymyxa.
Inhibits bacterial function
Bacitracin and polymyxin B are active against Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, Hemophilus influenzae, Klebsiella/Enterobacter species, Neisseria species and Pseudomonas aeruginosa bacteria. These antibiotics do not provide adequate coverage for Serratia marcescens.
Polymyxin B inhibits bacterial function by interacting with the phospholipid components of the cell membrane, which increases the permeability of the cell wall. It is active against many of the gram-negative bacteria. Bacitracin is bactericidal for many gram-positive and some gram-negative organisms. It interferes with bacterial cell wall synthesis by inhibiting the phospholipid receptors involved with peptidoglycan synthesis.
Polysporin ointment has proven to be effective in combination with other antibiotics. It is used with aminoglycosides and fluoroquinolones to add to the spectrum of coverage. Corneal infection is often caused by lid disease, and the addition of lid scrubs and Polysporin ointment accelerates the recovery.
I have encountered infrequent reactions to Polysporin. Within the past 6 months, I have had one 70-year-old woman with moderate blepharitis develop red, itchy lids after using the ointment for 1 week. Polysporin was discontinued, and TobraDex (tobramycin 0.3%, dexamethasone 0.1%, Alcon) ointment was substituted to treat the blepharitis and lid reaction. Within 2 to 3 days, she was not experiencing itching, and the redness had subsided.
A variety of treatment plans
Blepharitis (mild to moderate). Prescribe Polysporin ointment for use after lid scrubs two times per day for 2 weeks. The ointment can then usually be reduced to use at bedtime after cleansing the lids.
It is important to explain how to use the ointment and that vision will be blurred when the ointment is applied to the eye's surface. I usually recommend that the patient place a small amount of ointment on his or her finger and then rub the antibiotic on the lash margins. Patients are instructed to make sure the base of the lashes are coated with the ointment.
When treating mild to moderate blepharitis, I usually do not have the patient instill the ointment into the eye. Contact lenses should not be worn during the first 2 weeks of treatment. Hands must be washed before and after the ointment is applied.
Blepharitis (severe, ulcerative). Prescribe Polysporin ointment three to four times per day for the first week. Have the patient use warm compresses for 10 minutes three to four times per day and then scrub vigorously with one of the commercial lid scrubs.
The patient can then apply the ointment to the lid margins, and at night the patient is instructed to pull down the lower lid and instill a ribbon of ointment that is approximately 1 inch long into the lower fornix.
Often, the blepharitis is associated with meibomianitis or acne rosacea. These patients usually require oral antibiotics to facilitate the desired recovery. My oral antibiotic of choice is doxycycline. The usual dosage for an average-sized, healthy adult is 100 mg per day for 14 to 28 days for a flare-up of meibomianitis.
With acne rosacea or chronic meibomianitis, it may be necessary to prescribe the doxycycline with a higher dose initially and continue the medication for 3 to 6 months. The dosage can be reduced to 50 mg per day after 3 months.
Doxycycline should not be prescribed for children younger than 12 years or for pregnant women.
Adnexa abrasions or minor cuts. Prescribe Polysporin ointment four times per day on the cut or abrasion until the wound has healed.
Useful adjunct therapy
Conjunctivitis. Polysporin is a good adjunct to the aminoglycosides or the fluoroquinolones. Have the patient clean the lids before instilling the drops. After the drops, apply the ointment to the lid margins.
Mild cases of conjunctivitis are usually cleared with drops four times per day for 5 to 7 days and Polysporin ointment at night. Moderate to severe cases usually require lid scrubs, saline rinses, drops initially as often as every hour and Polysporin ointment four times per day for 5 to 7 days.
Use the ointment on the lid margins during the day, and apply the ointment to the lower fornix and lid margins at night. Remember to have the patient wash his or her hands, especially after touching the lids.
Bacterial keratitis. With most corneal ulcerations, I would start with Ciloxan (ciprofloxacin HCl, Alcon) or Ocuflox (ofloxacin, Allergan) and have the patient instill drops every 15 minutes for 6 hours. The antibiotic drops are then reduced to every 30 minutes for the next 18 hours.
Homatropine 2% or 5% is prescribed four times per day to relieve ciliary spasm and reduce the anterior chamber reaction.
Polysporin ointment is directed to be applied to the lids and lower fornix four times daily after lid scrubs, saline rinse, homatropine and antibiotic drop instillation. Ibuprofen 600 mg every 4 to 6 hours helps relieve pain and reduces the anterior chamber reaction.
After 24 hours, the cornea is re-evaluated, and a judgment is made as to whether the eye is stable. In the first 24 hours, the main concern is that the infection is not progressing. With most infections, it is too early to see much improvement. The antibiotic drop is usually reduced to every hour, and the other medications are continued as prescribed. If stomach upset is noted, it may be necessary to reduce or discontinue the ibuprofen.
Evaluate the eye daily until the pain has subsided and the lesion shows slight or no stain with fluorescein. The homatropine and ibuprofen can then be discontinued and the antibiotic drops reduced to four times per day for 5 to 7 more days. The Polysporin is usually reduced to bedtime use with continued application in the lower fornix and to lid margins for 5 to 7 more days.
Prophylactic treatment. When patching an abrasion or after foreign body removal, Polysporin ointment is an excellent antibiotic to use to prevent infection. It causes too much blurring for use as a prophylactic antibiotic during the day when the eye is not patched.
Polytrim (trimethoprim sulfate, polymyxin B sulfate, Allergan) or Ocuflox may be a better choice for use during the day.
Inexpensive, effective treatment
Polysporin is a broad-spectrum antibiotic that is on most formularies and is readily available at pharmacies. Excellent results are achieved when this medication is used for treating blepharitis. It can also be used in conjunction with other antibiotics for treating more severe infections.
Because polymyxin B and bacitracin are not available in injectable or oral forms, there is less concern for allergic reactions. When allergic reactions do occur, they are usually mild and easily rectified by discontinuing the ointment.
Polymyxin B/bacitracin ointment tops my list as the antibiotic prescription that I write most often as a primary care optometrist. It provides the practitioner with an inexpensive and effective treatment for lid disease and anterior surface infection.
For Your Information:
- Polysporin ointments available from Glaxo Wellcome, 5 Moore Drive, Research Triangle Park, NC 27709; (919) 248-2100.