Mary is a 70-year-old widow with a history of osteoarthritis. She has been self-medicating with over-the-counter acetaminophen, either extra strength (500 mg/tablet) or arthritis strength (650mg/tablet) for over a year now. In addition to osteoarthritis, she also has osteoporosis and gastroesophageal reflux. She presents with the complaint of backache and right knee pain, aggravated by climbing stairs. She describes her knee pain as 8 on a scale of 1 to 10: “I can stand the back pain, but the knee is awful.” She lives alone but has two supportive daughters nearby. They take her shopping and help with housework. On good days, she goes to the senior center for lunch and socialization. She was doing exercises at the Senior Center but stopped due to her knee pain. She does not smoke or drink alcohol, except at birthday parties and celebrations. She denies any medication, food, or environmental allergies. In addition to the acetaminophen, medications include calcium with vitamin D, Protonix (pantoprazole), and an annual intravenous infusion of Reclast (zoledronic acid). She also has been taking a dietary supplement of glucosamine/chondroitin for 3 months. She recently had a complete physical examination with electrocardiogram and laboratory tests and was told that everything was “normal.”