When to check blood tests after initiating isotretinoin (Accutane) for acne treatment?

From the Guidelines

Blood tests should be checked at baseline and 2 months after initiating isotretinoin for acne, and then as clinically indicated, including liver function tests, fasting lipid panel, and pregnancy test for patients with pregnancy potential. The most recent and highest quality study, published in 2024 in the Journal of the American Academy of Dermatology 1, suggests that routine monitoring of complete blood count is not necessary. According to this study, laboratory monitoring during isotretinoin treatment should include liver function tests, fasting lipid panel, and pregnancy test for patients with pregnancy potential. The risks of abnormal liver function tests and abnormal triglycerides and cholesterol levels are estimated to be relatively low, ranging from 0.8% to 10.4% and 7.1% to 39.0%, respectively 1. It is essential to monitor these laboratory tests to detect any potential abnormalities early on, as most changes occur within the first few months of treatment. Additionally, pregnancy testing is crucial for women of childbearing potential, as isotretinoin is highly teratogenic and must be avoided during pregnancy. The study also suggests that isotretinoin may improve quality of life and decrease symptoms of anxiety and depression in patients with acne, which is an essential consideration when weighing the benefits and risks of treatment 1. Overall, the monitoring of blood tests should be tailored to the individual patient's needs and risk factors, with a focus on detecting potential laboratory abnormalities and minimizing the risks associated with isotretinoin treatment. The previous study published in 2019 1 also supports the idea that routine monitoring of complete blood count is unwarranted, and that triglycerides and liver enzymes should be checked at baseline and two months into treatment, with more frequent monitoring with dose changes or as otherwise clinically indicated. However, the 2024 study 1 provides more up-to-date and comprehensive guidance on laboratory monitoring during isotretinoin treatment.

From the FDA Drug Label

Lipids Pretreatment and follow-up blood lipids should be obtained under fasting conditions. After consumption of alcohol, at least 36 hours should elapse before these determinations are made It is recommended that these tests be performed at weekly or biweekly intervals until the lipid response to isotretinoin is established. Liver Function Tests Since elevations of liver enzymes have been observed during clinical trials, and hepatitis has been reported, pretreatment and follow-up liver function tests should be performed at weekly or biweekly intervals until the response to isotretinoin has been established Blood lipid determinations should be performed before isotretinoin is given and then at intervals until the lipid response to isotretinoin is established, which usually occurs within 4 weeks

• Lipid tests and liver function tests should be checked before initiating isotretinoin therapy.
• These tests should be performed at weekly or biweekly intervals until the response to isotretinoin is established, which usually occurs within 4 weeks.
• Blood lipid determinations should be performed before isotretinoin is given and then at intervals until the lipid response to isotretinoin is established.
• For patients with diabetes, obesity, increased alcohol intake, lipid metabolism disorder or familial history of lipid metabolism disorder, more frequent checks of serum values for lipids and/or blood sugar are recommended 2.

From the Research

Blood Test Monitoring After Initiating Isotretinoin for Acne

• The frequency and timing of blood tests after starting isotretinoin for acne treatment have been studied to determine the optimal monitoring approach 3, 4, 5, 6, 7.
• Research suggests that in healthy patients with normal baseline lipid panel and liver function test results, repeated studies should be performed after 2 months of isotretinoin therapy 3.
• If the findings are normal after 2 months, no further testing may be required 3.
• However, other studies recommend continued monitoring of liver enzymes and lipids, as isotretinoin can cause alterations in these levels 6, 7.
• The majority of abnormalities in liver enzymes and lipids occur within the first month of therapy, with most being mild and not worsening over time 4.
• Routine complete blood cell count monitoring is not recommended, as clinically insignificant leukopenia or thrombocytopenia is rare 3.
• Elevated liver transaminases are detected infrequently, and significant elevations in triglyceride and cholesterol levels are more common 3, 6, 7.
• The use of ALT and AST as monitoring tools has been questioned, with some studies suggesting that GGT and CK may be more valuable in managing patients on isotretinoin therapy 5.