Several types of medication are used for knee problems, some to control pain and inflammation and others to interfere with various disease processes (see Table).
Acetaminophen. For pain relief, acetaminophen (Tylenol, other brands) is generally the first choice because it is effective and easy on the stomach. Do not exceed the recommended dosage of acetaminophen, however, because it can damage the liver, especially in heavy drinkers who may already have some liver damage.
NSAIDs. Nonsteroidal anti-inflammatory drugs such as aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve, Anaprox), and several others may be more effective than acetaminophen, particularly during sudden flare-ups of pain, because they are superior at reducing inflammation. There are also a number of prescription NSAIDs such as nabumetone (Relafen) and oxaprozin (Daypro). Stay within recommended dosages. Regular use of NSAIDs can produce gastrointestinal bleeding and ulcers, often without warning. Combining acetaminophen with a smaller amount of an NSAID may provide equivalent pain relief with a reduction in side effects. You can also ask your doctor about taking a proton-pump inhibitor such as esomeprazole (Nexium) or lansoprazole (Prevacid) to reduce the risk of gastric bleeding and ulcers.
COX-2 inhibitor. Celecoxib (Celebrex) is in a class of prescription NSAIDs known as COX-2 inhibitors, which relieve pain with less stomach irritation than traditional NSAIDs. Concerns about cardiovascular side effects mean it should be used only in cases in which a patient does not have heart disease, has tried other pain relievers without success, and is not taking blood thinners (anticoagulants such as warfarin).
Opioids. Another large class of pain-relieving drugs comprises the opioid medications such as codeine and oxycodone, which have morphine-like properties. The term opioid has, by and large, supplanted "narcotic" as the preferred term for these drugs because the latter term has legal and regulatory meanings. Opioids work by interacting with the receptors on brain and spinal cord nerves for the endogenous opioids, which are the body's natural painkilling substances. For orthopedic problems such as knee and hip conditions, opioids are used judiciously, often for only brief periods just before and after surgery, or in patients with severe pain who are not helped by or are unable to tolerate NSAIDs. Opioids are effective in masking pain but do not help inflammation. Care must be taken to avoid tolerance, which develops after just two weeks, and side effects such as dizziness can make it difficult for people to participate in physical therapy while taking these medications. Opioids can be habit-forming.
Corticosteroids. Corticosteroids, such as prednisone, reduce the body's ability to generate an inflammatory reaction. They relieve pain by reducing inflammation. Corticosteroids are credited with both treating and causing knee and hip problems. When first introduced in the 1950s, corticosteroids were regarded as miracle drugs because of the dramatic effect on patients with active rheumatoid arthritis, many of whom were able to literally throw down their crutches. But within a few years, the devastating effects of long-term use of oral corticosteroids became apparent: bone weakening, compression fractures of the back, diabetes, increased susceptibility to infections, cataracts, hypertension, and other health problems. Most side effects occur when these drugs are taken orally, but repeated corticosteroid injections into a joint can result in thinning of the cartilage and weakening of the ligaments. In the short term, though, corticosteroids can sometimes provide quick and dramatic relief.
Corticosteroid injections: How many is too many?
For osteoarthritis, most experts recommend limiting corticosteroid injections to no more than once every three to four months — and a maximum of roughly four injections in any given joint. Other experts point out that since most osteoarthritis patients will eventually need joint replacement surgery, and since artificial joints have a limited life span, corticosteroid injections are an effective way to buy some time and delay surgery as long as possible.