Irritation, inflammation, or ulcers of the esophagus. Hypocalcemia, spasms, twitches or muscle cramps, numbness or tingling in fingers, toes or around the mouth. Severe bone, joint or muscle pain. Osteonecrosis. Unusual thigh bone fractures. Back pain, heartburn, abdominal pain, pain in arms & legs, diarrhea, headache, muscle pain, flu-like symptoms. Allergic reactions eg, hives, difficulty of breathing, swelling of face, lips, tongue or throat, or feeling faint.