Creatine Phosphokinase Values during Low Starting Dose Isotretinoin Therapy

Background: The value of creatine phosphokinase (CPK) monitoring during isotretinoin therapy is still a matter of debate because of the rarity of muscular and kidney damage in this setting. The aim of the study was to investigate the incidence of CPK elevation during a low starting dose isotretinoin regimen and to discuss the clinical approach to patients with increased CPK. Methods: We reviewed the records of the acne patients from 2015 to 2018 at the University of Ferrara and at the University of Modena and Reggio Emilia. Routine clinical and laboratory follow-up was analyzed. Results: The records of 328 patients were included in the study. Abnormal CPK levels were observed in 5.5% of cases. Revised Leeds acne scores and visual assessment scale (VAS) measurements decreased significantly after isotretinoin therapy. Discussion: The adoption of the low starting dose isotretinoin regimen is associated with low incidence of CPK elevation. The finding of CPK over the conventional value of 5 times above the limit was rarely observed and was never associated with kidney damage. Therefore, it should be interpreted as a relatively benign phenomenon that does not require the interruption of isotretinoin therapy and that should be managed mainly through the reassurance of the patient.