Hi, Thank you for your question. Fosamax is contraindicated (meaning absolutely should not be used) in patients who have problems or abnormailities of the esophagus, patients who cannot sit up or stand for 30 minutes at a time, patients allergic to any of the ingredients in Fosamax, and patients who have a condition known as hypocalcemia. There is a warning against use in patients who have upper GI disease (ulcers, GERD, etc), cancer patients, patients with mental disease that would prevent them from understanding how to take the medication, patients with severe kidney disease, patients with vitamin D deficiency. There may be more warnings and precautions associated with Fosamax use. If you would like to read more about Fosamax, you can do so here. Best of luck, Casey