Mothers Pride

My mother, who is 80 and has osteoporosis, has been on Fosamax going on three years (first took the daily tab, could not tolerate so doctor put her on the 70mg. once weekly). Problem now is it seems to be affecting her colon/bowels. She is so constipated (never has been before), she seems to smother from her stomach and is always bloated with terrible gas. She stopped taking it for two weeks and was no longer constipated nor did she feel bloated. Only problem is that although she excercises daily (which is hard since she also has a 28 year old plastic hip joint) and takes two Calcium pills with Vit. D a day, she and I both worry about her bones. Has anyone tried taking Fosamax only once a month? Would that help her any after taking it for going on three years? Also, has anyone else had the terrible constipation and stomach bloating taking this drug? Would ask her doctor but she just got married and moved away. Any info would greatly be appreciated. Thanks!