Fosamax is a prescription drug used to treat osteoporosis and other bone problems. Fosamax's active ingredient is alendronate, typically taken orally in tablet form. The common dosage for Fosamax is 70 milligrams once weekly or 10 milligrams daily. For preventing osteoporosis, you might take 35 milligrams weekly or 5 milligrams daily. It's crucial to follow your doctor's instructions, usually taking the medication on an empty stomach in the morning and staying upright for 30 minutes after taking it to avoid esophageal damage. For steroid-induced osteoporosis, Fosamax might be unsuitable, and different dosages of alendronate are used. Fosamax is also used to treat Paget's disease of bone, at a dosage of 40 milligrams daily for six months. Long-term use of Fosamax requires regular monitoring of bone density to ensure effectiveness.