The inhibitory action of the prostaglandin synthesis is the basis for a supposed action on the bone of the NSAIDs (Non Steroidal Anti In ammatory Drugs), some of the most used drugs. There are, however, few published data on this action, except for the inhibition of bone healing by the NSAIDs. In the late nineties some studies demonstrating a positive effect of the NSAIDs on bone mass were edited. The positive effect seemed more evident for propionic NSAIDs (ibuprofen, ketoprofen...) and ASA, mainly if in association with the COX-2 inhibitors. Few years later some clinical studies, variously designed (prospectic, retrospective, and case-control), based on large population samples (a range from about 2,000 to 300,000 subjects), demonstrated, unexpectedly, an increase of the fracture risk in the NSAIDs users. The risk resulted variable for different NSAIDs molecules, but there were not a concordance among the studies, except for a not increased risk for ASA. An increased risk of a second hip fracture after the rst fragility hip fracture in the NSAIDs users, dose- and time-dependent, has been recently demonstrated in two propensity-score matching studies on a large popula- tion data-base in Taiwan. The cellular and molecular effects of the NSAIDs on the bone tissue have not yet well clari ed. An inhibition of the osteoblastogenesis, but also of the osteoclastogenesis has been demonstrated with different NSAIDs used in cellular coltures. These evidences could explain the increased fracture risk due to a decrease of the biomechanical properties of the bone, without a decreased bone mass.

Per i FANS è ipotizzata da tempo una loro azione sull’osso ed il loro ruolo inibitorio nella riparazione delle fratture la conferma, ma controverso è il ruolo nell’osteoporosi. Dagli anni 90 vari studi dimostravano un effetto positivo sulla massa ossea di FANS e aspirina, ma in studi successivi di vario disegno (da 2.000 a 300.000 soggetti prospettici o retrospettivi) il rischio di frattura risul- tava aumentato a seconda dei FANS, ma mai con l’aspirina. Non chiariti sono i meccanismi di azione sull’osso. Sembra che i FANS inibiscano l’osteoblastogenesi, ma anche la osteoclastogenesi, con un deterioramento delle competenze meccaniche, senza riduzione della massa ossea.