Effects of Isotretinoin on Serum Creatine Phosphokinase Levels in Patients with Acne Vulgaris

Abstract

Background and Design: It has been known that isotretinoin may cause rabdomyolysis besides its many side affects. The purpose of our study was to evaluate the effect of isotretinoin therapy with a cumulative dose of 120 mg/kg on serum creatine phosphokinase levels and muscle physiology in patients with acne vulgaris. Material and Method: A total of 66 patients with severe acne vulgaris were enrolled in the study and treated with isotretinoin twice daily at the dose of 0.6-0.8 mg/kg/day and for approximately 6.1 +/- 0.54 (3-7) months. Thirty-seven female (71.2%) and 15 male (28.8%) patients completed the study. The change in serum creatine kinase levels was measured before and monthly during the treatment course. Electromyography was performed in patients with a high serum CPK level and myalgia for the exclusion myopathy. All patients were evaluated with their laboratory findings and they were questioned for exercise habits and intramuscular injections. Results: The mean age and body weight was 24.6 +/- 6.1 years and 62.3 +/- 11.9 kg respectively. We have detected 7 patients having elevated (13.5%) serum CPK levels. Three of them had associating myalgia and muscle tenderness. The evaluation of these patients with EMG revealed no myopathy sign. (CPK values = 1000, 880,726 respectively) Only one patient with an elevated serum CPK was performing exercise. There was no history of intramuscular injection history in any of these patients. Conclusion: The use of standard isotretinoin therapy appears to have a relation with marked hyperCKemia with or without muscle-related complaints. Isotretinoin could have a potentializing effect on other myotoxicity inducers (drugs, infection, fever, muscular exertion). Although this phenomenon in isotretinoin-treated patients with acne appears to be validated as benign in nature, the clinicians must keep this side affect in mind and should monitorize serum CPK levels since there are some patients who had severe or persistent signs. (Turkderm 2008; 42: 56-9)