Laboratory Abnormalities Rarely Serious in Older Patients Receiving Oral Isotretinoin

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Expanding recommendations for less frequent laboratory monitoring of patients with acne ≥35 years old prescribed isotretinoin without baseline laboratory abnormalities is now supported.

The adverse event profile of isotretinoin in patients aged ≥35 years was explored in study data published in the Journal of the American Academy of Dermatology. Although previous meta-analyses reported infrequent laboratory abnormalities in patients receiving isotretinoin for acne vulgaris, these data were collected in patients aged <35 years. The present study extends these findings to older patients, in whom isotretinoin-related hematologic, hepatic, or lipid abnormalities were uncommon and rarely serious.  

Investigators conducted a retrospective analysis of patients who initiated their first oral isotretinoin therapy for acne between 2008 and 2016 at the Brigham and Women’s and Massachusetts General Hospitals in Boston, Massachusetts. Patients were grouped into those aged ≥35 years and those aged <35 years. Isotretinoin doses began at 0.5 mg/kg/day and were increased to 1 mg/kg/day, with a target cumulative dose of >120 mg/kg. Total cholesterol, triglycerides, alanine aminotransferase, white blood count, and platelet count were assessed at baseline and at monthly intervals during treatment. Patients with baseline laboratory abnormalities were excluded. Chi-squared and Fisher’s exact tests were used to evaluate differences in laboratory values between age strata.

A total of 596 patients were included in analyses, of whom 328 (55%) were women and 67 (11.2%) were ≥35 years old. Approximately half (n=279; 46.8%) identified as non-white. During treatment, abnormal total cholesterol was observed in 10.5% of patients ≥35 years old and 14.7% of patients <35 years old (P =.34). Abnormal triglycerides were present in 20.9% of patients ≥35 years old and 17.4% of patients <35 years old (P =.48). The highest abnormality severity was grade 1, observed in 26.9% of patients ≥35 and 33.5% of patients <35 (P =.28). None of the patients ≥35 had treatment interruptions or terminations due to laboratory abnormalities, and 15 interruptions and 6 terminations were observed in patients <35. Notably, patients ≥35 received lower mean monthly isotretinoin weight-based doses and longer durations of therapy than patients <35. However, the total cumulative dose was similar between age groups.

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Study limitations included the retrospective design and differences in monthly doses between age strata.

These data confirm previous findings that patients receiving isotretinoin for acne vulgaris do not often have laboratory abnormalities. Lipid abnormalities were most frequently observed in patients of both age groups, and typically presented in the first month of treatment. No patients ≥35 years interrupted or terminated treatment due to laboratory abnormalities. “Future studies should explore abnormalities in groups with differing isotretinoin doses and dose increase cadences, assess the causes of abnormalities, and include data from multiple institutions,” investigators wrote.  

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Sharma P, Tkachenko E, Mostaghimi A. A retrospective evaluation of routine isotretinoin laboratory 1 monitoring in patients above 35 years old [published online April 25, 2020]. J Am Acad Dermatol. doi: 10.1016/j.jaad.2020.04.106