Isotretinoin, retinoic acid (form of victamin A) derivative, is used to treat Pimples (Acne), Psoriasis, Cutaneous T-cell Lymphomas and Squamous Cell Skin Cancer. Trade names: Absorica, Accutane, Amnesteem, Claravis, Sotret, Roaccutane.
Rhabdomyolysis is when muscle tissue gets severely damaged and substances from inside the muscle cells leak out into the blood. This can lead to kidney damage. Severe rhabdomyolysis can be life-threatening. Symptoms and signs include muscle weakness, myalgias, and reddish-brown urine. Diagnosis of rhabdomyolysis is by history and laboratory confirmation of elevated creatine kinase (CK) of typically greater than 5 times the upper limit of normal.
Isotretinoin and Creatine Kinase (CK)
Isotretinoin has been reported to elevate creatine kinase, which may lead to fatal rhabdomyolysis. Approximately 25% to 51% of patients on isotretinoin report fatigue and myalgias, respectively, and 44% of patients also have elevated creatine kinase (CK)[1-3]. But there is neither consensus on the clinical signiﬁcance of, nor guidelines on how to manage, elevated CK on isotretinoin.
Marson and Baldwin  have illustrated the potential connection between muscle damage and isotretinoin therapy. They reported a large series of isotretinoin-treated patients who had elevations in creatinine kinase during therapy. A more recent patient had classic rhabdomyolysis and required hospitalization. Common features of those with repeated high elevations were male sex and vigorous exercise.
The creatine kinase (CK) is not routinely monitored in patients taking isotretinoin, however in consideration of potential linkage between isotretinoin and muscle damage, the laboratory tests eg. lipids, CK, GGT, and HCG, shall be ordered before therapy, at the first visit, with each dosage change, and to follow-up abnormalities.
- Webster GF, Webster TG, Grimes LR. Laboratory tests in patients treated with isotretinoin: occurrence of liver and muscle abnormalities and failure of AST and ALT to predict liver abnormality. Dermatol Online J 2017; 23(5):
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- Justin Marson and Hilary Baldwin. The creatine kinase conundrum: a reappraisal of the association of isotretinoin, creatine kinase, and rhabdomyolysis: The creatine kinase conundrum. The International Society of Dermatology. 27 December 2019.