How Safe is Safe?

Regarding the article Topical Treatment in Our Most Vulnerable Patients (January 2007), a sentence reads, Tobramycin is contraindicated ... Yet, a table on the next page contradicts this by listing tobramycin as pregnancy class B (not contraindicated). The package insert for Tobrex (tobramycin for topical ophthalmic use) clearly shows it is indeed class B; however, for the inhalant form of tobramycin, the package insert shows that it is class D.

This is an important issue to me because about two months ago, I prescribed topical tobramycinin the form of TobraDex (tobramycin/dexamethasone, Alcon), which is class Cto one of my pregnant patients for severe marginal keratitis with secondary iritis. I discussed with the patient the benefits vs. risks of treatment, and recommended lid closure and punctal occlusion after instillation to minimize systemic uptake.

The categorization of such drugs is worth clarifying, since there are medicolegal ramifications. For example, if ophthalmic tobramycin really were contraindicated, then I would not have met the standard of care in my recent treatment.

Brian Chou, O.D., San Diego


The authors respond:

Thank you for your comments concerning the article. You raise an important point, since ophthalmic tobramycin is indeed labeled as category B, according to the FDA. But few studies have been done on humans, and some sources report that animal studies have shown this drug, given at high doses in other forms, has caused birth defects and other problems in the developing fetus.

The main point: With careful precautions and patient education, this drug can be used when the benefits of its use outweigh the risks (as in a severe eye infection). This was the biggest challenge that we faced when researching and writing this article.

There is such a large gray zone for some of the drugs that it really is very difficult to determine whether a drug is safe. Luckily, there are many drugs to choose from, and the educated prescribing doctor will know to look up the drug before writing the script.

That was our main goal for the article: Give the doctor the general overview of the most commonly-used drugs and give tips on how to help the doctor look up more information on a drug before prescribing it.

Mary Bartuccio, O.D., Rachel A. Coulter, O.D., and Marc B. Taub, O.D.

Vol. No: 144:03Issue: 3/15/2007