A significant proportion of post-menopausal, patients treated with AI reports side-effects, especially bone pain. In such patients, the difficulties to treat pain and to clearly identify its causes may lead to treatment discontinuation. Ageing is associated with physiological modifications that may impair drug pharmacokinetics (PKs). The elimination can be altered, with decreased drug clearance (CL), resulting in an increased exposure to the drug, reflected by increased AUCs. The reported increases in AI exposure being around 50 %, an intermittent dosing schedule of 1 administration every other day could result in a similar drug exposure as compared to the usual daily schedule.