Q&A: following the three presentations, the panelists took questions from the audience.

Q: In order to deliver 3,000 [micro]g/ml of antibiotic to the middle ear in a patient with a ventilating tube, topical drops must be able to get down the tube. But if a patient has both a draining ear and purulence in the canal, can the drops still reach the middle ear?

Dr. Roland: This is variable and depends on the particular circumstances of each case. Facilitating penetration is one of the principal purposes of aural toilet, whether it is performed in your office with a microscope or by the patient at home with some sort of irrigation device. A variety of studies have shown that drops can and frequently do penetrate into the middle ear through tympanostomy tubes. Clearly, some of the failures of ototopical therapy are attributable to failures of delivery, so we cannot know for certain how well the drug penetrates in every case.

But is there evidence that drugs ever penetrate? Yes, there is. Is there evidence that they penetrate often and with regularity? Yes, there is. Are there some cases where penetration does not occur? Surely.

Q: As a pediatric otolaryngologist, I realize that the quinolones, especially with the addition of dexamethasone, represent a major advance in clinical practice because now we can treat problems like we could not before. Some of my colleagues say they are seeing fungal over-growth as a consequence of quinolone therapy. What is the best way to use the quinolones judiciously so that we can limit the risk of fungal overgrowth?

Dr. Roland: I personally do not see fungal overgrowth very often. There is some evidence that neutral pH drops are more likely to cause fungal overgrowth than are slightly acidic drops. I believe that a slightly acidic preparation has an advantage in this regard, but I don't know that it tan prevent fungal overgrowth in every case.

Dr. Haynes: I have seen very few cases of fungal overgrowth, but it seems to be more commonly associated with ofloxacin, which has a neutral pH, than with ciprofloxacin, which is acidic.

Q: You've made it clear that the quinolones are the drug of choice. But I see a number of patients with otorrhea who are referred to me by family practitioners who have already tried a quinolone drop. I can usually clear their infection with aural toilet and by switching to a powder or a different drop. So a quinolone is not an option in these cases.

Dr. Roland: I would venture to say that if these patients had undergone aural toilet earlier, the quinolone would have been more effective. But I stand by what I said in that I don't believe there are any good indications for the use of any drops other than a quinolone, because of the potential for side effects.

Dr. Haynes: Again, I believe that virtually all failures of topical therapy are failures of delivery; the drop is just not getting to the source of the infection. Treatment failures, in general, are not secondary to bacterial resistance. With the sort of antibiotic concentrations and the sort of pathogens we are treating, it would be very unusual to see a bacteriologic failure with a quinolone. Of course, treatment failures will occur that may indicate advanced disease requiring surgery (i.e., tympanomastoidectomy).

Dr. Roland: A report will be published soon--probably in the January issue of Otolaryngology-Head and Neck Surgery--in which a consensus panel will recommend that ototoxic drops be avoided as first-line therapy and be used only if there is a good reason to use something other than a drop that is not ototoxic.