I've been taking Cacit 500 for many years for osteopoenia; two years ago I was prescribed Fosamax as I'd dipped into the osteoporosis band and continued taking both ... Cacit in the evening, Fosamax before breakfast one day a week (Thursday). By chance I was at the chemist's and happened to be buying both medications to the chemist's surprise, because "these two products are incompatible". What exactly does this mean. I seem to be doing well on both and have had no side effects.