The present invention relates to a new use of a compound of the formula (I) ##STR00001## wherein R.sub.1 is NH.sub.2, piperazin-1-yl, 4-methylpiperazin-1-yl,4-methyl-1,4-diazepan-1-yl or 4-ethylpiperazin-1-yl; R.sub.2 is hydrogen, fluoro, CH.sub.3, CH.sub.2CH.sub.3, OCH.sub.3, CF.sub.3 or OCF.sub.3; R.sub.3 is hydrogen, CH.sub.3 or fluoro; as a free base or a pharmaceutically acceptable salt thereof, in the manufacture of a medicament for the prevention and/or treatment of bone-related disorders, osteoporosis and increasing bone formation, bone mineral density. The present invention further relates to a method of prevention and/or treatment of these disorders.