Benefits of aminoglycoside drops still outweigh the risks. (Rebuttal).

The findings by Dr. Rutka and his colleagues that commercially available gentamicin/betamethasone drops do enter the middle ear space through a pressure-equalizing tube and can be ototoxic were unique and significant.1 However, it is important to note that these ears were not inflamed and that these patients had no history of chronic infection. It is also significant that these patients had a severe underlying vestibular disorder, which led to the decision to ablate the vestibular dysfunction with gentamicin. It is well known that hydropic ears are more susceptible to the effects of gentamicin.

Bedside testing

I agree with Dr. Rutka' s statement that our bedside examinations in the United States are lacking. Tests for head-shaking nystagmus and oscillopsia are not performed on patients who have chronic ear disease at any point during the course of management. Nevertheless, vertigo is an easily recognized neurotologic symptom, and I believe that most otologists would not miss it, especially in patients with chronic ear disease and a severe degree of ataxia.

Even if the physician were to miss vertigo, the patient would not. I agree that recovery of vestibular function does occur, even when it is caused by intentional ablation, and that patients can often compensate for a unilateral loss. But I believe that patients who are being treated for chronic ear disease will report dizziness, even if the physician does not specifically ask them about it. I do not believe that patients merely assume that dizziness is part of a chronic ear process.

Quinolone alternatives

I concede Dr. Rutka's s point that there are safe alternatives. In their consensus report published in 2000, Hannley et al wrote, "Where a perforation exists or a patent tympanostomy tube is present, quinolone drops offer superior safety and efficacy."2 They also wrote, "The decision to use a potentially ototoxic agent such as aminoglycoside is optimally made only after nonototoxic drops have failed."

Personally, I agree with these statements. As I mentioned in my earlier argument, I do not use aminoglycoside drops for chronic ear disease in my practice because I have the option of using quinolone drops, which are safer and which have just as good a bacteriologic profile.

I do use some ototoxic drugs, such as gentamicin and acetic acid, in some cases when I have no good alternative. But all of our practices are dynamic, and further research might persuade me to abandon these agents altogether. For now, however, their benefits still outweigh their risks. Nevertheless, I predict that the use of ototoxic drops in the United States will continue to decline.

References

1. Kaplan DM, Hehar SS, Bance ML, Rutka JA. Intentional ablation of vestibular function using commercially available topical gentamicin-betameshasone eardrops in patients with Meniere's disease: Furtber evidence for topical eardrop ototoxicity. Laryngoscope 2002;1 12:689-95.

2. Hannley MT, Denneny JC III, Holzer SS. Use of ototopical antibiotics in treating 3 common ear diseases. Otolaryngol Head Neck Surg 2000;122:934-40.