Expert shares tips on isotretinoin dosing at AAD 2014

Denver - On the final day of the 72nd Annual Meeting of the American Academy of Dermatology, one expert shared clinical pearls regarding isotretinoin dosing for acne.

Jerry Kim Leng Tan, M.D., says to boost their patients’ chances of experiencing sustained remission of severe acne via isotretinoin, dermatologists may need to beef up their dosing. He is adjunct professor, department of medicine, University of Western Ontario, Windsor campus.

The optimal cumulative threshold for isotretinoin remains unknown, he says.

“But it’s higher than we thought” when the drug debuted. An early study suggested cumulative doses no higher than 120 mg/kg to 150 mg/kg given over three to five months (Shalita AR, Cunningham WJ, Leyden JJ, et al. J Am Acad Dermatol. 1983;9(4):629-638).

In recent years, Dr. Tan says, research suggests a cumulative dose of 220 mg per kilogram - and perhaps higher. To prevent relapse, “We’re not even talking about 120 mg/kg to 150 mg/kg. We’re moving the bar farther up.”

The time restrictions initially applied to the drug have for the most part lifted, he says. In one recent study, patients got a mean of 1.6 mg/kg /day for up to 290 days (Cyrulnik AA, Viola KV, Gewirtzman AJ, Cohen SR. Int J Dermatol. 2012;51(9):1123-1130).

In practical terms, Lawrence F. Eichenfield, M.D., added during a separate session, very few of his patients require three or more courses of isotretinoin yearly. He is chief of pediatric and adolescent dermatology at Rady Children’s Hospital and professor of pediatrics and medicine (dermatology) at the University of California, San Diego.

Dr. Tan also took issue with the methodology of many earlier isotretinoin studies. In particular, he says, “A cancer patient knows what ‘remission’ means - no disease.” However, dermatologic research in acne varies in this regard, he says. Some studies define clearance as merely the absence of nodules. Other yardsticks allow for patients with some number of clinical manifestations remaining after treatment to be classified as clear.

However, Dr. Tan says, “Our patients don’t want ‘no nodules.’ They want no acne. Why don’t we stop treating when we don’t see any more acne?” This practice also would establish an appropriate baseline for gauging relapses in future acne studies, he says.

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