Drugs sold to increase one's bone density such as Fosamax and Boniva are riddled with negative side effects and reasons not to take it. Here is a good article from News With Views going over how extremely dangerous they are. 

These drugs can lead to severe pain, are highly inflammatory and destructive, are linked to an increase risk of potentially life threatening atrial fibrillation, and can even cause your jaw to rot.

To top it off, bone density scanners are routinely misread, leading to misdiagnoses, and the prescribing of drugs to those who don't need it.

They work in two ways:

By killing osteoclasts – the carpenter cells in charge of the demolition part of the remodeling process. New healthy bone cannot be built by osteoblasts until old worn bone has been removed by osteoclasts.

By gluing calcium onto bone in abnormal ways, providing the appearance of greater bone density. However, this is like nailing a piece of plywood over a hole in the wall. Yes, there is something there, but it is not a normal wall and it does not have the proper strength of a normal wall.

Once bisphosphonates arrive at bone they are stuck there forever, as a completely abnormal substance residing within and on the bone. The human body has no enzyme system that can break them down. Thankfully, after one year the biological activity of the poison is reduced; however, it is still stuck in the bone indefinitely. It is not a trivial issue to give a patient a toxic drug that accumulates in bones and is highly active even after it is stopped, which explains why some of the patients did not get rid of their pain even after discontinuing the drug.

Such a therapy may have some advantages in a situation of very poor health wherein a person is rapidly losing bone. The idea is that it is better to have some bone, regardless of its true condition, compared to no bone. Indeed, these drugs were first approved for diseases of rapid bone loss, such as Paget’s disease. In such high risk cases it can be demonstrated that the risk of fracture can be reduced. In other words, bones glued together with Fosamax may be better than really weak bones in horrid health.

Overall, I see that these drugs are highly destructive and should be used sparingly in society. 

Know what you're taking, why you are taking it, and educate yourself thoroughly on all its side effects.  Question your doctor and research his suggestions through Google.

Ultimately, you are in charge of your health, nobody else cares to take over for you.