Background: Musculoskeletal side effects related to isotretinoin are frequently reported. This study aimed to investigate the effect of oral isotretinoin treatment on muscle strength. Our second aim was to evaluate whether there was a correlation between the serum creatine phosphokinase (CPK) level, a specific marker of muscle breakdown, and muscle strength.
Methods: This study included 30 patients who presented to our hospital and were started on oral isotretinoin treatment for acne vulgaris and 30 patients in the control group who were given local treatment. Age, sex, height and weight of the patients were recorded, and the body mass index (BMI) was calculated. The hamstring and quadriceps muscle strengths of the non-dominant side were evaluated in all patients using an isokinetic dynamometer, and the peak torque (PT) values were recorded. In the isotretinoin group, isokinetic measurements were performed again in those that completed six-month drug treatment and compared with the initial PT values.
Results: The two groups were similar in terms of age, sex, and BMI (p > 0.05). There was no significant difference between the isotretinoin and control groups in terms of muscle strength at the beginning of the treatment (p > 0.05). No significant change was observed in hamstring and quadriceps PT values in the isotretinoin group after 6 months of treatment compared to baseline (p > 0.05). No statistically significant correlation was found between the serum CPK level and hamstring and quadriceps muscle strength (p > 0.05).
Conclusion: Oral isotretinoin doesn't alter muscle strength. There is no relationship between the serum CPK levels and muscle strength.
Trial registration: ClinicalTrials.gov NCT04626817.
Keywords: Creatinine phosphokinase; Isokinetic; Isotretinoin; Muscle strength.