Povidone-iodine offers inexpensive alternative for paediatric conjunctivitis

Sean Henahan
in Los Angeles

POVIDONE-iodine ophthalmic solution should be considered to treat bacterial and chlamydial conjunctivitis, especially in underdeveloped countries where topical antibiotics are often unavailable or costly, a new study suggests.

Researchers in Los Angeles, California and Philippine General Hospital in Manila collaborated on the first ever prospective, masked and controlled comparison trial of povidone-iodine ophthalmic solution and neomycin-polymixin B- gramicidin solution.
Some 459 children with acute conjunctivitis were randomised to receive one of the treatments four times daily until symptoms resolved.

The patients or their families evaluated the degree of ocular inflammation each day, with the ophthalmologist checking the patient once a week.
Povidone treatment proved to be as effective as the more costly antibiotic regimen in terms of the number of patients cured after one and two weeks, according to principal investigator and professor of paediatric ophthalmology, Sherwin J Isenberg MD.

“Povidone-iodine 1.25% ophthalmic solution is an effective and inexpensive treatment for conjunctivitis in children, with important economic and medical implications for underdeveloped countries,” he notes.
The protocol enrolled patients ranging in age from one month to 21 years, with a median age of four years. All patients presented with ocular inflammation and discharge of less than two weeks duration.

Patients who had used ocular antibiotics in the past two weeks were excluded from the study. The researchers obtained conjunctival and eyelid margin cultures in all cases.
Negative cultures were considered evidence of viral infection, as long as appropriate clinical signs were present. Some 80% of cases of acute conjunctivitis are associated with bacteria in the US. However, in this study, conducted in the Philippines, nearly 60% of cases evaluated were attributed to viral infection. Povidone was no more effective than antibiotic in viral cases.

Patients employed alternately assigned treatments until symptoms resolved. Some 60% were cured within seven days. All patients were cured by the third week of treatment. The time to cure was the same in both treatment groups, regardless of the microorganism involved.

Treatment success did not depend on gender or age. However, younger patients did tend to be cured faster. Patients with chlamydia infections took the longest time to heal.

In order of prevalence, cultured microorganisms included Haemophilis, Moraxella, Staphylococcus, Streptococcus (pneumoniae, veridans, epidermidis), Acinetobacter and N gonorrhoeae.

When culture tests indicated gonococcal infection, patients also received intramuscular ceftriaxone. Patients diagnosed with chlamydia received additional treatment with oral doxycycline.

Acute conjunctivitis may be the most common ocular problem paediatric specialists treat. While many cases resolve spontaneously, conjunctival infections can develop into keratitis, corneal ulceration and scarring and even blindness.

And what’s more, there is a greater likelihood of more serious complications being seen in the developing world, where malnutrition and shortages of topical antibiotics are common problems.

Povidone-iodine has a broad spectrum of antimicrobial activity, including against chlamydia. It also shows in vitro activity against virtually all viruses and fungi.
The drug is very well tolerated, with few side-effects or allergic reactions. Interestingly, while it is typically used for prophylaxis, little study has been done on its potential for treatment.

“Povidone was used for treatment in a few small uncontrolled studies. I think that it was not used out of fear of toxicity to the cornea and the mindset that it is only a ‘preventative’ medication and not used for treatment. Indeed, it is used before many other types of surgery including general surgery and gynecological procedures,” he noted.

Povidone, with its low cost and high efficacy, can make an important difference in the developing world. But the fact that it does not induce bacterial resistance also makes it an attractive option in the developed world as well, he noted.

Antibiotic ointments or solutions can cost at least four times as much as povidone-iodine. Povidone iodine can be compounded easily by local pharmacists. It can be prepared without difficulty from powder or stock solutions.
Dr Isenberg reports that some 400,000 children worldwide are now blind due to corneal ulceration. Many of these cases began as conjunctivitis which subsequently infected the cornea and resulted in blindness. Often, there is an associated cause such as Vitamin A deficiency, malnutrition or rubeola.

“In many underdeveloped countries, there are no antibiotics available to treat the conjunctivitis, thus allowing it to progress to keratitis. Povidone-iodine is available worldwide and is very inexpensive. Now that we have demonstrated its effectiveness and lack of toxicity, treatment will be available where there was no treatment before,” Dr Isenberg said.

In a previous study in Kenya in which Dr Isenberg participated, he found that povidone was cheaper and better than either silver nitrate or erythromycin for the prevention of ophthalmia neonatorum.

“The treatment of trachoma is now a major interest of ours. The chlamydia treated in the Philippines and in our prior trial in Kenya dealt with a different type of chlamydia — although the same species.

“If also effective against trachoma, one can imagine periodically (weekly or monthly) treating all children in a village with a drop of povidone-iodine to prevent or treat the infection when it is active. Obviously, further studies need to conducted,” he said.
The complete details of Dr Isenberg’s study are available in the November 2002 issue of the American Journal of Ophthalmology.

Sherwin J Isenberg MD
UCLA Jules Stein Eye Institute, California, U
Email: isenberg@ucla.edu

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