Benzaclin

Dr. Shalita: Benzoyl peroxide is the most potent topical antibacterial as a single agent because it is bactericidal, whereas the topical antibiotics are bacteriostatic. The only advantage topical antibiotics have, which is why I like to use them in combination with BP, is that they have anti-inflammatory properties. In terms of antibacterial activity, P. acnes are resistant to antibiotics. Dr. Berson clearly demonstrated many years ago that P. acnes is resistant to erythromycin, and Dr. James J. Leyden of the University of Pennsylvania published an article in the British Journal of Dermatology showing that Staphylococci are resistant to erythromycin as well. But if you combine benzoyl peroxide with erythromycin--or now, clindamycin--you eliminate the bacterial resistance to the antibiotic; you eliminate all those strains that were resistant or less sensitive. For some unexplained reason, you get a greater decrease in the bacteria with the combination therapy than you do with BP alone. It's not a huge difference, but there is some difference. Plus, you reap the anti-inflammatory benefits of the antibiotics.

There are really two antibacterial combinations available to us now. We've had the BP-erythromycin combination around for a long time, and it is very effective and very helpful. However, it's an alcohol formulation, so some patients may be experiencing excessive drying, whereas the benzoyl peroxide/clindamycin formulations are both aqueous, so they are better tolerated. I saw some data, I believe from Dr. Leyden, where the benzoyl peroxide/clindamycin combo was slightly superior clinically and bacteriologically to the benzoyl peroxide/erythromycin. And that's basically what I use. I rarely if ever use the topical antibiotic alone. If, for example, I'm going to use the clindamycin wipe as an individual agent, which is very convenient to the patient, I'll have the patient use a benzoyl peroxide cleanser either at the same time or at another time. Clindamycin is much more stable than erythromycin when used in combination with a cleanser or anything else.

Dr. Shupack: Benzoyl peroxide has to be either reconstituted at the time of dispensing, or refrigerated. I assume that's to maintain its stability.

Dr. Shalita: No, it's the other way around. Benzoyl peroxide is a potent oxidizing agent, so whatever you put with it eventually is going to be oxidized. That's why you have to make it up fresh or have it refrigerated before dispensing it. There's a difference between the two products: one, BenzaClin, is compounded by the pharmacist at the time of dispensing, so theoretically it's a fresh product at the time; while the other product, Duac,[TM] is already mixed by the manufacturer and is kept refrigerated until the time of dispensing.

These are good products, and the overall majority of patients are probably getting the correct medication and enjoying satisfactory improvement.

Dr. Shupack: Are two applications a day better than one?

Dr. Brand: If you were using only the one combination product, two applications would be better than one. I usually don't use a combination product as the only treatment, so I would generally do one application a day of each product, using one product in the morning and a different one at night. Usually one of them is a retinoid.

Dr. Berson: When you're told that benzoyl peroxide is bactericidal and antibiotics are bacteriostatic, you might ask why a combination of the two should be used as opposed to benzoyl peroxide alone? The answer, as Dr. Shalita explained, is that the antibiotic has some anti-inflammatory properties, so the combination product is probably better than benzoyl peroxide alone. And I'd like to point out that when we give someone one of these benzoyl peroxide/antibiotic combination products plus a retinoid, we are essentially giving them three treatments, although in two preparations.

Dr. Berson: In the anti-inflammatory category, we should talk about sodium sulfacetamide and sulfur products, because we are seeing a new product every day on the market.

Dr. White: There have got to be ten. I've never seen anything like it.

Dr. Shalita: It's because the products don't have to be approved by the FDA: they're grandfathered in. These products were already on the market when Dr. Shupack and I started our residency. They're old enough to be studied as part of what one doctor has called "paleodermatology."

I'd just like to reiterate what's been said about the BP/clindamycin and BP/erythromycin combinations being less irritating than BP alone in the same vehicle.

Dr. Robins: To make sure we've clarified everything, do either BenzaClin or Duac have any advantages over the other?

Dr. Shalita: Each has its own little peculiarities.

Dr. Brand: They're both excellent products. One good thing with the benzoyl peroxide and clindamycin formulations is that they don't require refrigeration like the earlier combinations with erythromycin. There's a place for both of these.

Dr. Shalita: Actually, you don't have to refrigerate the new erythromycin packs either.

Dr. Brand: That's true.

Dr. Robins: And they recommend still keeping Duac refrigerated.

Dr. Shalita: No, just the pharmacist keeps it refrigerated.

Dr. White: What's the reason that pharmacists have to refrigerate it, if once they hand it to someone it doesn't matter?

Dr. Shalita: Because as soon as you mix benzoyl peroxide and clindamycin you slow down any breakdown.

Dr. White: So once they dispense it to you, you don't need to refrigerate it. But if the pharmacist has it for three months in the pharmacy and doesn't refrigerate it, what happens?

Dr. Shalita: There's an expiration date on it.

Dr. Robins: Therefore, there is an advantage to mixing it fresh, because then you know are getting the maximum strength.

Dr. White: That's true.

Dr. Shupack: With Duac, even before it gets to the pharmacist, you have to trust that the interstate carriers of this stuff maintain steady refrigeration.

Dr. Shalita: It's shipped in refrigerators.

Dr. Robins: Like Botox.

Dr. Shalita: Yes.

Dr. Robins: What is it refrigerated with, [CO.sub.2] dry ice? You get Botox in a box, and they call you the day before to tell you it's coming. They want you to be there to receive it, because it's refrigerated.

COPYRIGHT 2004 Journal of Drugs in Dermatology, Inc.
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