Hello, Welcome and thanks for your query. I understand your concern regarding the side effects of Fosamax, but if you follow instructions of taking it on an empty stomach and avoid lying down or bending for the next 2 hours, there is hardly any problem and you are unlikely to develop any esophagitis. Vitamin D3 does not correct the osteopenia and the brittleness of your bones due to the same and hence cannot be considered a substitute. So don t worry, you can take Fosamax with the precautions mentioned and you have little chance of developing problems. Even if you do, it can be easily managed and often only requires discontinuation of the medicine. Take care,