Bone-scintigraphic examinations in patients treated with retinoids: a prospective study.

Possible early side-effects of retinoid treatment on bones were studied with the aid of bone-scintigraphy. Isotretinoin treatment (1.0 mg/kg daily for 4 months) was given to 18 patients with acne. Fifteen patients with psoriasis received etretinate treatment (0.7-1.0 mg/kg/day) for 4 months. In the group treated with isotretinoin, pathological uptake of radiolabel was found in three cases, while in the group treated with etretinate, no bone changes attributable to treatment were found. During isotretinoin treatment, a decrease in growth-plate activity was observed. Bone-scintigraphy is considered to be a suitable method for early screening for bone changes occurring in retinoid treatment.