Doctors have long prescribed nonsteroidal anti-inflammatory drugs (NSAIDs) to ease the pain and inflammation of arthritis and other types of pain. They achieve their benefits by inhibiting certain inflammation-causing chemicals in the body called prostaglandins (PG). NSAIDs block enzymes in the body, called cyclooxygenase (or COX), that play a role in prostaglandin production. Prostaglandins are mediators of inflammation in the joints. Traditional NSAIDs inhibit both COX-1 and COX-2. However, it has been found that COX-1 plays an important role in protecting the stomach lining; thus, its inhibition can lead to the stomach irritation and ulcers seen when people take most NSAIDs. It appears that for the control of arthritic and other painful symptoms, it is more important for a drug to block COX-2, which is produced in the body in the setting of inflammation.
Thus, medical scientists have sought to develop newer NSAIDs that are less likely to cause such gastrointestinal (GI) problems. There have been some debates about which drugs are more specific for COX-2 than others, which relates to different methods of testing the drugs. The most agreed-upon system of classifying the COX specificity of NSAIDs divides the agents into three groups:
The literature on GI side effects with these medications is extensive and still somewhat controversial, but the weight of the evidence still suggests that both the COX-2 selective and COX-2 specific agents have fewer GI side effects than older NSAIDs, as well as fewer of the more serious GI side effects, such as bleeding or perforation of an ulcer.
For the rest of this discussion, the term "COX-2s" will be used to include the COX-2-selective agent celecoxib (Celebrex). There is not sufficient literature at the moment to allow us to clearly separate the relative safety between these selective and specific drugs, and the choice is often made based on the physician's impression of their relative effectiveness. Overall, the COX-2s appear to be equally effective in controlling inflammation compared to the older, less selective NSAIDs, but they are considerably more expensive. Thus, the COX-2 inhibitors are used in patients who are at high risk for stomach irritation, including: the elderly; those with a history of NSAID-induced stomach irritation or intolerance; and those taking other drugs that increase the risk of stomach problems; or those who have other diseases (like heart or lung problems) that appear to increase the risk of ulcers.
For some patients, the risk of ulcer is so high that the physician may choose to give a COX-2 selective or specific agent and also add a medication to protect the stomach (see below). For other patients, the ulcer risk may simply be too high to recommend using these drugs at all, as in a patient who is actively being treated for a documented ulcer.
If any of the following guidelines are not clear, or if you think it does not apply to you, discuss the issue with your physician.
Although these drugs appear to be less likely to irritate the stomach than traditional NSAIDs, it can happen.
The FDA placed the following black box warning regarding GI symptoms with Celebrex®:
Celecoxibis contra-indicated in patients with allergy to sulfa-containing drugs (sulfonamides). Such drugs include the antibiotic trimethoprim-sulfamethoxazole (Bactrim, Septra). If you are thinking of taking celecoxib, make sure that you do not have a history of allergy to such drugs. If you aren't sure if a drug you had a bad reaction to fits in this category, ask your physician. If you are allergic to sulfa-containing drugs, do not take celecoxib.
Rofecoxib (Vioxx), a COX-2 specific agent, was removed from the market on 9/30/04 due to questions of increased risk of heart attacks and strokes. Users of the remaining COX-2 inhibitor, celecoxib (Celebrex), or COX-2 selective agents, such as meloxicam (Mobic) should be aware that these drugs are not blood thinners. Therefore, some patients whom their physicians feel are at higher than average cardiac risk may need to be given low-dose aspirin to help reduce heart attack risk. Even though adding aspirin to one of these agents may increase risk of ulcer, for a number of patients this risk may be worth taking, in view of the need for heart protection. However, although there is very good evidence that low-dose aspirin helps protect against heart attacks in patients with coronary disease, it is not yet clearly established that this effectiveness still applies in patients taking medications such as Celebrex or Mobic – or any of the NSAIDs (nonsteroidal anti-inflammatory agents).
Also, the FDA has required a block box warning about cardiovascular thrombotic events be placed in the package description of all NSAIDs, including COX-2 specific and selective agent, and patients at high risk for cardiovascular disease need to weigh the risks and benefits with their physician before taking any NSAID or COX-2 specific or selective agent. The “black box warning” for Celebrex related to cardiovascular risk reads as follows:
Serious skin reactions have occurred in people taking COX-2 inhibitors. These are rare occurrences, but have included potentially life-threatening hypersensitivity reactions. Because many of these reactions were voluntarily reported after the drug was marketed, it is not possible to estimate their frequency or whether they are indeed related to the drug. Severe skin rashes were a major reason for the withdrawal of valdecoxib (Bextra), another COX-2 specific NSAID, from the market, according to the FDA. Therefore, if you experience any rash while you are taking Celebrex, stop taking it immediately and call your doctor.
When you are trying on of these drugs for the first time, take the full dose prescribed every day, unless instructed otherwise. It may take as long as two weeks to build up to a "blood level" of the drug, and the drug may not help very much until then. If you take the drug irregularly, you may never know whether it actually can help you. This could lead to your being switched to a second drug when the first one actually could have helped. Each new drug you take carries a risk of allergic reaction (such as skin rash). Therefore, it's important to find out if a drug can help you before switching to another.
Do not exceed the dose of the drug prescribed. The extra benefit is usually small and the increased risk is significant.
If you are taking the medicine regularly and miss a dose, take it as soon as possible. However, if it is almost time for your next dose, skip the one you missed and go back to your regular schedule. Do not take a double dose.
If your arthritis improves, discuss with your physician the possibility of decreasing your dose of the NSAID.