Systemic therapy for acne

January 18, 2009

Kohala Coast, HI - Newer oral antibiotics have a reduced side-effect profile and increased efficacy in the treatment of acne, said Hilary Baldwin, M.D., at the Winter Clinical Dermatology Conference.

Kohala Coast, HI

- Newer oral antibiotics have a reduced side-effect profile and increased efficacy in the treatment of acne, said Hilary Baldwin, M.D., at the Winter Clinical Dermatology Conference.

Oral antibiotics used for the treatment of acne include tetracycline, doxycycline and minocycline, now that erythromycin is no longer effective at killing P. acnes in the United States, according to Dr. Baldwin.

"The mechanism of action of oral antibiotics is two-fold," she said. All of the antibiotics previously listed kill P. acnes, but additionally, the tetracyclines act as anti-inflammatory medications.

In terms of the ability to kill P. acnes as a whole, minocycline appears to do better than the other drugs. The tetracylines (TCNs), on the other hand, are very good anti-inflammatory products, Dr. Baldwin said.

"The tetracycline class of antibiotics has numerous side effects to be concerned with. First, we have the change in bacterial flora that gives many of our female patients yeast infections, but more significantly the TCNs, especially doxy and tetra, cause some sensitivity in gastrointestinal distress," she said.

Another change in oral antibiotics is formulation variations, which have occurred in the recent past, according to Dr. Baldwin.

"Extended-release minocycline tablets and delayed-release, enteric-coated doxycycline gives us once-a-day dosing alternatives and fewer restrictions on when the patient can actually take the medication.

"And we know that numerous studies have demonstrated that when you decrease the frequency and reduce the number of restrictions put on the patients that compliance increases," she added.

These new formulations have also succeeded in reducing side effects, Dr. Baldwin said.

According to one long-term study on extended-release minocycline, which has not yet been published, urticaria was only seen in one patient, there were no cases of hyperpigmentation, and dizziness, vertigo, nausea and vomiting was extremely low.

When looking at ANA positivity, Dr. Baldwin said, "It’s important that we look at the background data so that we can really assess whether or not a little increase in ANA positivity on medication is due to the drug or just background noise."

A recent study of 125 healthy individuals comparing them to patients with lupus and scleroderma was able to demonstrate that in the "healthy" population 32 percent were positive at 1:40, 13 percent at 1:80, 5 percent at 1:160 and 3 percent at 1:320.

"So the take-home message for this study was that a positive ANA does not mean that a person has lupus and that clinical features are needed before you can assess what that positive ANA actually means," Dr. Baldwin said.

Delayed-release, enteric-coated doxycycline, on the other hand, has shown to reduce potential for GI upset because of the enteric coating and delayed absorption in the small intestine, Dr. Baldwin explained.

Azithromycin is another oral antibiotic that some physicians think should replace erythromycin, she added.

"It probably should replace erythromycin, but the real question is, should erythromycin be there to begin with since it doesn’t kill P. acnes in the United States anymore," she said.

Antibiotic resistance is another factor when considering acne therapy. Resistance rates have been rising dramatically since the 1970s. Minocycline, however, is catching up at the slowest rate while still maintaining the best efficacy for killing P. acnes.

"One of the ways that we can reduce this issue is by co-administration of benzoyl peroxide," Dr. Baldwin suggested.

Another option for treating acne in women is hormonal therapy, said Dr. Baldwin. "We can try oral contraceptives, because oral contraceptives reduce ovarian, and to some extent, adrenal androgen precursors, and they also increase sex hormone binding globulin."

There are currently three drugs that are approved by the FDA, but probably all the oral contraceptives are effective in treating acne, Dr. Baldwin said.

Androgen-receptor blockers are also very useful in hormone therapy. They are especially effective in women who have therapy-resistant acne and those who also have hirsutism and alopecia, she said.

Lastly, Dr. Baldwin said the efficacy of isotretinoin is unquestioned, but the side effects and media hype around it can be difficult for patients to understand.

"Virtually all patients respond to this drug, with 60 percent to 80 percent of them showing a permanent remission," Dr. Baldwin said, and there is no proven evidence that isotretinoin causes depression.

"There is no support of a causal relationship between isotretinoin and depression,” she said, "but we can’t rule out a weak association, so it’s smart to weigh the risks and benefits. I tell my patients, we believe isotretinoin cures depression because most of our patients are depressed because of their acne," Dr. Baldwin said.

Lastly, Dr. Baldwin said that iPLEDGE has become less cumbersome for patients and physicians.

"Those of you who backed out in the very beginning, you really need to reconsider, because I think most of us would agree that it is no longer such a complicated issue," she added. DT