Point and Counterpoint about a New Drug for Relief of Chronic Low Back Pain
Most people know what drugs to take for back pain: anti-inflammatory medicines such as ibuprofen. Ibuprofen and many other over-the-counter and prescription anti-inflammatories are known as NSAIDs (non-steroidal anti-inflammatory drugs). COX-2 inhibitors are a relatively new class of NSAIDs. They work by blocking the COX-2 enzyme, which triggers pain, inflammation, and fever. One of the benefits of COX-2 inhibitors is that they tend to have fewer effects on the digestive system than other NSAIDs.
These authors tested a specific COX-2 inhibitor in patients with long-term low back pain (LBP). Almost 700 patients, who had LBP for an average of 12 years, reported their levels of back pain and function. They were then divided into three groups. The first group got a standard dose of the drug, the second group got double that dose, and the third group got a placebo pill. Everyone the medication once a day in the morning.
After one month, all the patients were retested. Both COX-2 groups had significantly less pain than the placebo group. They also showed better back function. There were no significant side effects, although patients on the smaller dose had fewer problems. The authors conclude that this drug is very safe and effective at the lower dose for patients with long-term LBP.
A doctor from the University of Washington wrote a commentary following the original article. He points out some limitations of the study. First, all the patients were already taking NSAIDs. That means the researchers already knew that NSAIDs helped these patients' condition and that the side effects weren't too bad for them. People who tried NSAIDs and either didn't get pain relief or had bad side effects were automatically not part of this study. Testing COX-2 inhibitors in the general population of people with LBP would almost certainly show less success and more side effects.
Second, this was a "flare" study. That means that patients had to come off of medications they were already taking, which typically causes pain to flare up for awhile. Then the patients began taking the study drug. This makes the study drug seem to be especially effective because it relieves some of the worst symptoms patients have had for a long time.
The doctor also questions whether a one-month follow-up is enough in patients who have had LBP for an average of 12 years, and whether the pain relief was really good enough to consider making COX-2 inhibitors the treatment of choice.
The bottom line according to this doctor is that there need to be further studies of COX-2 inhibitors to really tell how well they work for all patients. He does not consider this article to be proof that this drug is a better treatment for patients with chronic LBP.
Nathaniel Katz, MD, et al. Efficacy and Safety of Rofecoxib in Patients with Chronic Low Back Pain: Results from Two Four-Week, Randomized, Placebo-Controlled, Parallel-Group, Double-Blind Trials. In Spine. May 1, 2003. Vol. 28. No. 9. Pp. 851-859.