In osteoarthritics, Doxycycline, a tetracycline, was found to reduce knee joint space narrowing by 40% at 16 months and 33% at 30 months compared to placebo. In another study, after noticing a rapid reduction of inflammation in an OA case on Sulfa-Trimethoprim (Cotrimoxazole), a case series was done which again noted “high improvement in pain, joint limitation, and patients’ global assessment of disease activity” in 6/10 cases.
1) ARTHRITIS & RHEUMATISM Vol. 52, No. 7, July 2005, pp 2015–2025
Effects of Doxycycline on Progression of Osteoarthritis Results of a Randomized, Placebo-Controlled, Double-Blind Trial
Kenneth D. Brandt,1 Steven A. Mazzuca,1 Barry P. Katz,1 Kathleen A. Lane,1 Kenneth A. Buckwalter,1 David E. Yocum,2 Frederick Wolfe,3 Thomas J. Schnitzer,4 Larry W. Moreland,5 Susan Manzi,6 John D. Bradley,1 Leena Sharma,4 Chester V. Oddis,6 Steven T. Hugenberg,1 and Louis W. Heck5
- 430 randomly assigned women age 45-64
- Doxyxyline 100 mg BID or placebo
- Tibiofemoral JSN was measured manually in fluoroscopically standardized radiographic examinations performed at baseline, 16 months, and 30 months.
- 40% reduction narrowing versus placebo at 16 months and 33% reduction at 30 month
- monitoring pain levels didn’t work because pain levels were too low, though flares were less common
– “when administered for 5 days prior to surgery, doxycycline at this dose significantly reduced the levels of total and active collagenase and gelatinase in extracts of the OA cartilage” – an anti-inflammatory effect. There are studies showing protective effects on OA in the animal model.
2) Chemotherapy 2007;53:1–9
Is Osteoarthritis an Infection-Associated Disease and a Target for Chemotherapy?
Alexander Rozin abstract
- Cotrimoxazole (sulfamethoxazole/trimethoprim – septra, bactrim) was used in cases of OA. This drug has been known to have anti-inflammatory properties.
- One DS strength tablet daily
- The clinical course of refractory knee OA improved …in 6/10 patients as soon as 6 weeks of Su-Tmx prophylaxis for recurrent UTI.
- The question was raised whether OA was a low grade infection
- Bacterial gut flora that was altered by use of antibiotics was another idea. This was supported by the thought glucosamine – chondrointin might work though its effect on the gut:”A recent trial by Biggee et al.  showed low levels of human serum glucosamine after ingestion of glucosamine sulfate relative to the capability for peripheral effectiveness. Another recent trial showed that a small amount of chondroitin sulfate may cross the upper intestine tract but, in the distal tract (cecum and colon), the molecule effectively degraded  . Therefore, and given other unpublished data, there is a high suspicion of interaction of intestinal flora and glucosamine and chondroitin sulfate.”
Comment – I am using doxyxycline in acne and to prevent deterioration of aortic aneurysms. One of the latter cases had rather severe OA hip that has not surfaced since she had a steroid shot some years ago. I now wonder if the doxycycline has helped her OA. One wonders if this might prove a safer alternative to NSAID’s in the elderly in responsive cases.
On another note, subchondral bone loss (bone loss under area of OA) is very common and use of Risedronate (a biphosphonate = bone builiding osteoporosis drug) prevents it. What that means I do not know…
Rheumatology 2007;46:257–264; A 2 yr longitudinal radiographic study examining the effect
of a bisphosphonate (risedronate) upon subchondral bone loss in osteoarthritic knee patients
J. C. Buckland-Wright et al
free article here