Effects of isotretinoin on the thyroid gland and thyroid function tests in acne patients: A preliminary study.

BACKGROUND Isotretinoin is widely used in the treatment of acne. AIMS We investigated the effects of isotretinoin on thyroid function tests and thyroid volume in acne patients. METHODS In this prospective study, a total of 104 acne patients were included. Sixty-six patients were treated with isotretinoin for at least 4 months. Thirty eight patients were included in the control group. The levels of thyroid stimulating hormone, free triiodothyronine, free thyroxine, antithyroglobulin and antithyroid peroxidase antibodies were measured and a thyroid ultrasound was performed in all the subjects before treatment and 4 months after treatment. A "p" value of < 0.05 was considered significant. RESULTS In the isotretinoin-treated group, thyroid stimulating hormone levels increased significantly during isotretinoin treatment (P = 0.018). Free triiodothyronine, free thyroxine, anti-thyroid peroxidase levels and thyroid volume decreased significantly during treatment (P = 0.016, P= 0.012, P= 0.006, P = 0.020 respectively). LIMITATIONS The major limitation of this study is the lack of follow-up data after the cessation of isotretinoin therapy in acne patients. CONCLUSION Patients treated with isotretinoin should be monitored with thyroid function tests.