Thread by @DrJohnBarbieri

What is the optimal approach to monitoring patients being treated with #isotretinoin for #acne? In this Tweetorial, let’s review the evidence for best practices! #dermtwitter #MedEd 1/13

First, why do we monitor labs?

Benefits:
-Prevent severe adverse effects
-Guide dosing

Downsides:
-Pain
-Fear
-Cost

2/13

With respect to current practices, as of 2016, over 40% of clinicians were checking CBCs, LFTs, and lipid panels monthly! And rates of monitoring do not appear to be decreasing over time. Is this optimal? 3/13
ncbi.nlm.nih.gov/pmc/articles/P…

Lipids are the most commonly monitored lab. The stated purpose of lipid monitoring is to identify elevated triglycerides to prevent isotretinoin associated pancreatitis. Mild lipid changes are common and plateau early in the course of therapy. 4/13

However, in our study of 1863 patients treated with isotretinoin, clinically meaningful triglyceride abnormalities (>500mg/dL) occurred in fewer than 1% of patients and 76.9% of these patients continued their course of isotretinoin. 5/13
ncbi.nlm.nih.gov/pmc/articles/P…

In addition, a review of 25 cases of isotretinoin associated pancreatitis found only 4/25 (20%) had elevated triglycerides, calling into question whether monitoring lipids can help identify patients at risk of pancreatitis. 6/13
onlinelibrary.wiley.com/doi/abs/10.111…

With respect to LFTs, clinically meaningful abnormalities (grade 3+, >5x ULN) were detected in <0.5% of patients and were just as common at baseline (before even starting isotretinoin) as on therapy suggesting that they may not be medication related. 7/13

No significant white blood cell count or platelet abnormalities were noted. These findings are consistent with other studies and the AAD guidelines suggesting that there is no clinical utility to routinely monitoring complete blood count. 8/13
jaad.org/article/S0190-…

What about baseline labs? A study of 735 patients found that baseline lab abnormalities are not highly predictive of abnormalities during treatment and rarely lead to treatment modification, which suggests they may be low value to guide management. 9/13
karger.com/Article/Abstra…

What about CPK? Although isotretinoin can rarely be associated with rhabdomyolysis, patients are usually symptomatic. In addition, athletes often have CPK 500-1000 (normal <250) and runners can be 20x normal after a marathon. 10/13

There are currently no guidelines for monitoring CPK. However, I do not routinely check given stress/cost of false positives and since unlikely to change management due to rhabdomyolysis being exceedingly rare. Consider checking if severe myalgias 11/13
onlinelibrary.wiley.com/doi/abs/10.111…

So what should we do? One proposed approach is to check lipids (TGs) and LFTs (AST/ALT) at baseline and peak dose. If not notable abnormalities, then no further testing is required. This approach has the potential to save $20-131 million annually. 12/13
jaad.org/article/S0190-…

In summary, we are likely overmonitoring patients on isotretinoin, leading to unnecessary fear, stress, and cost. Checking TGs and AST/ALT at peak dose +/- baseline is a reasonable approach that balances costs with the low risk of meaningful abnormalities during treatment 13/13

How do you approach monitoring of patients on isotretinoin?
What questions do you have about isotretinoin monitoring?