The invention provides methods and compositions for reducing or inhibiting bone resorption, osteoclast differentiation and stimulation and the loosening of medical prostheses by administering a compound or agent that modulates an adenosine receptor such as the adenosine A2A receptor, in particular, an agonist of an adenosine A2A receptor. The invention also extends to pharmaceutical compositions comprising such an agent that modulates an adenosine receptor such as an adenosine A2A agonist and to prosthetic devices containing such an agent that modulates an adenosine receptor such as an A2A agonist on one or more surfaces or within the prosthetic device such as, for example, suspended in the cement forming the prosthetic device.