Doxycycline For Osteoarthritis
Study results reported in Arthritis & Rheumatism (July 2005 issue) suggest that treatment with the antibiotic doxycycline may slow the progression of osteoarthritis. Doxycycline is an antibiotic belonging to a class of medicines called "tetracyclines."
About The Study
Researchers compared the use of doxycycline to placebo, using about 400 obese women with knee arthritis as study participants. Researchers analyzed the impact of doxycycline on the joint space of the affected knee.
The study participants were randomized into two groups, receiving either 100 mgs. of doxycycline twice daily or placebo for up to two and a half years.
Following 16 months of treatment, results indicated that the average loss of joint space in the affected knee was 40% less among participants taking doxycycline than those who took placebo.
At the end of the two and a half year period, the loss of joint space was 33% less in the group who took doxycyline than in the group who took placebo.
Doxycycline was also associated with less reports by patients of a 20% or more increase in knee pain. Researchers though acknowledged the average level of pain was low in both groups.
Researchers said that this was the first major study of doxycycline as a potential treatment for osteoarthritis. More studies will be needed to confirm these results.
Comments from Dr. Scott Zashin about the doxycycline and osteoarthritis report
Rheumatologist, Dr. Scott Zashin, commented, "First of all, this is a unique study in that it was a relatively long term study that looked at a medication not only relieve pain, but also prevent progression of osteoarthritis of the knee. While the study did not clearly show that oral doxycycline was effective in reducing pain, there was evidence that there was less progression of osteoarthrits (i.e. less cartilage loss) in patients on the antibiotic. The authors make it clear that the antibiotic was felt to work based on its anti-inflammatory properties, and not due to its anti-bacterial effect."
"What does this study mean for patients with osteoarthritis? Two clinical issues important to patients and doctors include whether the medication relieves joint discomfort and whether or not the patient may require a joint replacement in the future. Based on this study, it is difficult to recommend long term doxycyline for relief of symptoms. On the other hand, it is possible that patients taking the antibiotic may be less likely to require a joint replacement in the future due to a decrease in joint damage on radiograph."
"Unfortunately to answer this question, a much longer study would be needed. Some questions to consider are whether patients would need to remain on antibiotics indefinitely to help decrease joint damage and prevent subsequent joint replacement and what are the potential side effects from this long term regimen. The other question is whether or not a 30 month treatment with the drug will in itself, decrease the chances that in the long run, those patients would be less likely to require surgery. Hopefully, this cohort of patients can continue to be studied in the future to help answer these questions."