Investigating Isotretinoin Inconsistencies

In a JAMA Dermatology article published online on December 2, Lee et al challenged the commonly held belief that laboratory studies should be monitored frequently for patients on isotretinoin. In this systematic review and meta-analysis, abnormalities in liver function tests (LFTs), complete blood cell count (CBC), and lipid panel were compared in a set of 22 randomized clinical trials and 4 retrospective studies (1574 patients). Results revealed changes in the mean laboratory values from baseline (99% CI) of the following: aspartate aminotransferase, 22.67 U/L (19.94–25.41 U/L); alanine aminotransferase, 21.77 U/L (18.96–24.59 U/L); alkaline phosphatase, 88.35 U/L (58.94–117.76 U/L); white blood cell count portion of CBC, 6890/µL (5700–8030/µL); lipid panel (triglycerides, 119.98 mg/dL [98.58–141.39 mg/dL]; total cholesterol, 184.74 mg/dL [178.17–191.31 mg/dL]; low-density lipoprotein cholesterol, 109.23 mg/dL [103.68–114.79 mg/dL]; high-density lipoprotein cholesterol, 42.80 mg/dL [39.84–45.76 mg/dL]).

Although these laboratory values were altered as noted above, only 0.5% of patients exhibited test results statistically above or below the mean laboratory values. Additionally, of these laboratory abnormalities, mean changes were not considered to be high risk based on National Institutes of Health clinical center reference ranges.

What’s the issue?

Last year the residents in-training in our department noted variations in what each faculty member was recommending for isotretinoin laboratory monitoring. Practices ranged from initial then monthly full CBC, LFTs, and lipid panel, to those who only checked these laboratory results initially and at 1 month, to those who only performed review of systems-germane parameters. After reviewing the literature, individual preferences, and cost comparisons, a consensus was reached: tests for aspartate aminotransferase, alanine aminotransferase (in lieu of LFT panel), total cholesterol, triglycerides (in lieu of lipid panel), and relevant pregnancy screens would be performed initially, at month 1, and at month 2.

Lee et al also determined that monthly laboratory testing may not be necessary, especially for this low-risk category of patients, but further study is required to determine if there is a standardized way to approach laboratory testing from a safety and economic standpoint, as each dermatologist who prescribes isotretinoin can identify individual cases in which laboratory monitoring was helpful or uncovered individual comorbidities or toxicities in addition to instances where blood work was prohibitively redundant and expensive.

What is your approach to blood work in isotretinoin patients, and can you identify individual patient populations that require more or less stringent laboratory monitoring?

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