WAILEA, HAWAII (FRONTLINE MEDICAL NEWS) – Many physicians perform laboratory monitoring monthly when prescribing isotretinoin for severe acne, but recent evidence indicates that’s excessive, according to Julie C. Harper, MD, president-elect of the American Acne and Rosacea Society.

She pointed to a meta-analysis of isotretinoin studies, which she called “a game changer” in her own dermatology practice in Birmingham, Ala.

“I used to check labs monthly, too, but I’ve changed my practice as a result of this study. I perform a lipid and hepatic panel at baseline and after 2 months of isotretinoin therapy, and if those numbers are okay I don’t check them again,” she said at the Hawaii Dermatology Seminar provided by the Global Academy for Medical Education/Skin Disease Education Foundation.

The investigators published a meta-analysis of 26 studies including 1,574 isotretinoin-treated acne patients with serial laboratory values available ( JAMA Dermatol. 2016 Jan;152[1]:35-44 ). They were particularly interested in patterns of elevation in triglycerides because that’s the most common lab abnormality associated with the use of isotretinoin. Indeed, the package insert states that, in the original clinical trials, one in four isotretinoin-treated patients developed high triglycerides.

The meta-analysis demonstrated that triglyceride levels rose by a mean of 45.3 mg/dL after 8 weeks on isotretinoin. Notably, however, the mean difference in triglycerides between baseline and 20 weeks was essentially the same at 45.6 mg/dL.

“Therefore, if you’re going to have a change in triglycerides, you’re going to have it early. If it’s good at week 8, it should be good at week 20. And if it’s not good at week 8, you probably ought to keep checking,” Dr. Harper said.

Similarly, there was no substantial late effect of isotretinoin on total cholesterol.

The investigators determined that they had insufficient data to draw conclusions regarding late changes in liver function tests. For guidance on that score, Dr. Harper turned to an earlier study of nearly 14,000 isotretinoin-treated patients led by Lee T. Zane, MD , a dermatologist at University of California, San Francisco, and medical director at Anacor.

Dr. Zane and his coinvestigators found that 1.5% of patients experienced a moderate elevation in transaminase levels, and no one experienced high-risk or grade 2 elevations in transaminases, triglycerides, or total cholesterol. Dr. Zane and his coinvestigators also concluded that monitoring white blood cells, platelets, and hemoglobin was meritless ( Arch Dermatol. 2006 Aug;142[8]:1016-22 ).

“I’m not checking white blood cells, platelets, or hemoglobin. I check only triglycerides, total cholesterol, and hepatic function – and a pregnancy test, of course,” Dr. Harper said.

“I’ve practiced for 17 years,” she continued. “I’ve given a lot of people isotretinoin. And I would agree with Lee Zane – we don’t see elevated liver function tests very often with this drug, and when we do there’s often another explanation for why they’re high.”

In her own practice, when a patient on isotretinoin develops a high triglyceride approaching 300 mg/dL, the first thing she does is recheck it and make sure the patient is fasting. If it’s a true elevation, she pulls the dose back because this is a dose-related side effect. She also recommends that the patient begin taking fish oil supplements at a starting dose of 2 g/day. In a handful of refractory patients, she prescribes fenofibrate.

The exceptions she makes to her policy of no further lab testing if the first 2 months are problem free are patients with polycystic ovary syndrome, central obesity, or outright metabolic syndrome, since they are probably already at increased risk for developing lab abnormalities.

Dr. Harper said her acne patients are pleased with her change in practice regarding laboratory monitoring. Coming in for monthly blood work is inconvenient. And some patients really, really do not want to be stuck with a needle.

“We’re saving money, too,” she noted.

Dr. Harper wasn’t the only dermatologist who found the recent meta-analysis persuasive. The report was accompanied by an editorial by physicians uninvolved in the study entitled, “Isotretinoin Laboratory Test Monitoring – A Call to Decrease Testing in an Era of High-Value, Cost-Conscious Care” ( JAMA Dermatol. 2016 Jan;152[1]:17-9 ).

She reported serving on speakers’ bureaus for Allergan, Bayer, Galderma, LaRoche-Posay, Promius, and Valeant.

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