Often we encounter inflammatory disease with a confirmed or questionable underlying infective component. It may be that we are simply concerned about development of infection when prescribing a steroid. Blepharitis, keratoconjunctivitis, chalazia and inflammatory stages of microbial keratitis are just a few instances in which a combination antibiotic/steroid medication is optimal for effective treatment.
Unless the situation mandates the use of a fourth generation fluoroquinolone as an adjunct to a steroid, TobraDex remains the "go-to" drug for our profession.
Efficacy and safety
TobraDex, a tobramycin/dexamethasone combination, has a well-accepted effective aminoglycoside that addresses the typical bacteria that we encounter in eyelid disease and the other entities for which I would use this drug. Tobramycin is most effective against gram-negative bacteria, especially Pseudomonas, but it is also effective against most gram-positive bacteria.
For short-term use, this drug is an excellent cost-effective choice for killing bacterial ocular pathogens, in combination with its steroid counterpart. Rarely is it used long enough to produce any significant side effects, unless the patient is pre-sensitized. Although a fourth generation antibiotic/steroid combo might be a good alternative, none are marketed to date.
The steroid is usually the main component that I am interested in when prescribing TobraDex. Poorly controlled inflammation may lead to significant ocular damage, so my goal in using a combination drug is to knockout inflammation. Two recent studies, presented at ARVO 2005, prove the efficacy of dexamethasone. The first concluded that dexamethasone was more effective than loteprednol at reducing neutrophil release, a key component of the inflammatory cascade. The other found that tobramycin/dexamethasone significantly decreased the clinical signs of inflammation when compared with tobramycin/loteprednol.
Similarly, tobramycin/dexamethasone demonstrated clinically and statistically significant improvements in the total ocular surface scores when compared with tobramycin/loteprednol. Having appreciated excellent patient responses to TobraDex and its history of documented efficacy, this proven drug is a "no-brainer" to prescribe in my practice. Considering that I use steroid combination drugs for short-term treatment, my concern about steroid responder issues is minimal and certainly not a reason to use a different steroid. It's well-documented that it can take three to five weeks before a steroid responder will demonstrate a rise in IOP, well after the duration of therapy when I prescribe TobraDex.
Another consideration is availability. Most third party carriers cover TobraDex. Every time I prescribe a drug that is not on the patient's formulary, I spend time on the phone with the patient, pharmacy and/or carrier. It is time poorly spent. TobraDex is also safe and approved down to two years of age and conveniently available in both ointment and drop formulations.
We have had the luxury of transitioning from the days of Blephamide to the "Gold Standard" of TobraDex. A time-tested and proven formulation, it is my first choice when selecting a combination drug for my patients. I see no scientific evidence to dispute its success or a compelling reason to jump ship. If the diagnosis is appropriate to treat with a combination antibiotic/steroid, TobraDex should be your drug of choice.
BY GLENN S. CORBIN, O.D., Reading, Pa.
Dr. Corbin is in private group practice. He serves on the Adjunct Faculty at Pennsylvania College of Optometry and lectures nationally.
Copyright Boucher Communications, Inc. Jun 2005
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