A. Thornton , N. Valecha , E. Paver , R. Wong , D. Rubel
Introduction: Elevated levels of creatine kinase (CK), an
enzyme leaked into the bloodstream during cellular stress
such as muscle damage, has been associated with
isotretinoin use.
Serious muscle damage including fatal
rhabdomyolysis has also been reported.
However the majority of patients with elevated CK levels are asymptomatic, and only a minority of patients with severe myalgia
have elevated CK levels.
Furthermore baseline CK level is
influenced by age, gender and exercise regularity and
intensity.
Therefore it is unclear whether elevated CK
levels are significant, whether baseline levels should be
measured, and whether asymptomatic patients with
elevated CK levels should be given cautionary advice
regarding exercise while taking isotretinoin.
This study is part of a pilot study investigating the relationship
between acne, isotretinoin, serum CK levels, exercise
and oral protein supplements. We report the baseline
CK levels in a cohort of patients before commencing
isotretinoin, and the relationship with background exercise
frequency, intensity and duration.
Method: Approval was granted by the ACT Health Human
Research Ethics Committee. Patients aged 12–35 years with
acne requiring isotretinoin were prospectively recruited
from a private practice over a 12 month period. Information
about usual exercise behaviour including type, frequency,
intensity and duration was collected by survey. Serum CK
level prior to commencing isotretinoin was recorded. Data
were analysed using SPSS 22.0 software.
Results: CK level was above the laboratory reference range
in 9% (4/44) patients. CK levels were correlated to gender,
exercise intensity, duration and acne grade. Age and BMI
were not associated with CK level.