Short-term isotretinoin treatment decreases insulin-like growth factor-1 and insulin-like growth factor binding protein-3 levels: does isotretinoin affect growth hormone physiology?

BACKGROUND: Isotretinoin is an effective treatment for acne vulgaris. However, it has numerous side-effects. It was previously reported that serum growth hormone (GH) levels decreased with isotretinoin treatment. OBJECTIVES: To analyse whether isotretinoin has any effects on insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP3) and GH levels. METHODS: Forty-seven patients aged 21.5 +/- 5.1 years (mean +/- SD) with acne vulgaris were included in this study. Isotretinoin therapy was initiated at a dose of 0.5-0.75 mg kg(-1) daily and then adjusted to 0.88 mg kg(-1) daily as maintenance dosage after 1 month. Screening for biochemical and hormonal parameters was performed just before initiation and after 3 months of isotretinoin treatment. RESULTS: IGF-1 and IGFBP3 levels decreased significantly after treatment (P < 0.01), while GH levels did not change. Post-treatment, significant increases were seen in aspartate aminotransferase, total cholesterol, low-density lipoprotein cholesterol, triglycerides and low-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio (P < 0.0001) while high-density lipoprotein cholesterol levels were significantly decreased (P < 0.0001). CONCLUSIONS: Isotretinoin therapy may have an effect on GH physiology, and further studies are needed to understand this association.