isotretinoin and Osteoporosis

The synthetic retinoids, the vitamin-D-derivatives etretinate and isotretinoin, have substantially enlarged the therapeutic arsenal in dermatology. They are primarily used in severe cases of acne and cornification disorders. In the majority of cases, long-term treatment is necessary. Certain side effects in the skeletal system can occur, e.g., osteoporosis, premature epiphyseal closure, and changes similar to DISH (diffuse idiopathic skeletal hyperostosis). We discuss the reports in the literature and our own observations in 31 patients treated at the Westphalian Wilhelms University in Muenster, as well as at the Technical University in Munich. In 3 out of 31 patients treated by retinoids on a long-term basis, skeletal changes were found radiologically as a result of the retinoid medication.

Topics: Adolescent; Adult; Calcinosis; Child; Etretinate; Female; Humans; Hyperostosis, Diffuse Idiopathic Skeletal; Isotretinoin; Male; Middle Aged; Osteoporosis; Radiography; Skin Diseases; Spinal Osteophytosis; Time Factors; Tretinoin

Osteoporosis has been observed with chronic hypervitaminosis A but has not been established as a toxic effect of synthetic retinoid therapy in humans. This cross-sectional study was designed to assess bone mineral density (BMD) during long-term therapy with the retinoids etretinate or isotretinoin. Twenty-four patients were evaluated for osteoporosis with the standard techniques: single- and dual-photon absorptiometry. They received 50 g or more of etretinate (15 patients) or isotretinoin (nine patients) for 2 years or longer for the treatment of skin disease (ichthyosis [nine patients], Darier's disease [six patients], xeroderma pigmentosum [four patients], skin cancer [three patients], or psoriasis [two patients]). In each of the two treatment groups, BMDs (measured in grams per square centimeter) were measured at five standard sites (ie, lumbar spine, femoral neck, trochanter, Ward's triangle, and radius) and evaluated against a standardized database to control for age, sex, and weight. In addition, for each measurement site, BMDs (controlled for age, sex, and weight) were compared between the two groups, as a direct control for each other.. Compared with those of the age-, sex-, and weight-matched controls, the BMD values of the etretinate group were significantly decreased at four of the five measurement sites: femoral neck (90.6%, P = .0001), Ward's triangle (87.8%, P = .0001), trochanter (87.8%, P = .0012), and radius (85.0%, P = .039). In contrast, the BMDs in the isotretinoin group did not differ from control values except for an elevation at the lumbar spine (P = .039). When the two groups were compared, the mean BMDs were significantly lower in the etretinate group when measured at the lumbar spine, trochanter, and radius (P < .05).. This study identified osteoporosis in patients who received long-term therapy with etretinate but not isotretinoin. Prospective studies of BMD would be useful to further define retinoid-associated osteoporosis.

Topics: Adult; Aged; Bone Density; Cross-Sectional Studies; Etretinate; Female; Humans; Isotretinoin; Keratolytic Agents; Male; Middle Aged; Osteoporosis; Time Factors

13-cis-retinoic acid (13-cis-RA, isotretinoin) is used to treat severe recalcitrant acne. Other retinoids have adverse effects on bone. Recent studies of human patients treated with 13-cis-RA have had varying results, perhaps because of variability among patients and the lack of control groups. The effects of retinoids have been studied in rodents, but little information is available regarding the effects of clinically relevant retinoid doses as evaluated by use of bone densitometric techniques. We treated rats for 15 or 20 wk with 13-cis-RA, all-trans-RA, or soybean oil (control) by gavage. We used dual-energy X-ray absorptiometry, histomorphometry, and histologic evaluation to evaluate effects on bone. Spontaneous long bone fractures occurred in some rats treated with 15 mg/kg all-trans-RA daily. Bone mineral density, bone mineral content, bone diameter, and cortical thickness of the femur were reduced in rats treated daily with 10 or 15 mg/kg all-trans-RA or 30 mg/kg 13-cis-RA. The lumbar spine was not affected. Although the effects of 13-cis-RA were not as dramatic as those of all-trans-RA, further study of the effects of 13-cis-RA on long bones is warranted.

Topics: Absorptiometry, Photon; Administration, Oral; Animals; Bone Density; Bone Resorption; Dermatologic Agents; Disease Models, Animal; Female; Humans; Isotretinoin; Male; Osteoporosis; Rats; Rats, Sprague-Dawley; Species Specificity; Tretinoin

Topics: Animals; Bone Diseases, Metabolic; Calcification, Physiologic; Humans; Isotretinoin; Osteoporosis