Antimicrobial from the tetracycline group — Doxycycline — successfully used in the treatment of patients with bacterial infections. In addition to a wide range of antimicrobial activity, doxycycline has other positive properties that can be used in medical practice. The drug has been shown to have the ability to inhibit cartilage breakdown. Thus, doxycycline can be used to treat patients with osteoarthritis.

On the basis of preclinical data American rheumatologists conducted the first long-term clinical trial on the basis of six clinical research centers in the United States, which was to determine the feasibility of doxycycline in the treatment of patients with osteoarthritis, especially in patients affected knee joints. Study results published in the July issue of «Arthritis and rheumatism» for 2005., Evidence that doxycycline can slow the destruction of articular cartilage. Scientists emphasize the need to further study the effectiveness of this drug in eliminating the symptoms of osteoarthritis. The trial enrolled 431 overweight women aged 45 years–64-year-old with moderate osteoarthritis of one of the knees. Patients were randomized into two groups.

Patients in the main group received 100 mg of doxycycline twice daily for 30 months, while patients in the control group — placebo. The groups of patients were approximately homogeneous in terms of demographics, body mass index, types of drugs taken to relieve pain, and objective signs: radiological manifestations of osteoarthritis and functional disturbances in the affected joint. The rate of progression of osteoarthritis was judged by the degree of joint gap narrowing on radiographs obtained before the study, at 16 months, and 30 months after the start of the study. Joint pain severity assessed every 6 months after withdrawal of all nonsteroidal anti-inflammatory drugs and pain medications. 71% of patients completed the treatment program completely and their adherence to the medication regimen was 91.8%. After 30 months, radiological examination of the joints was performed in 85% of the patients included in the study. After 16 months of treatment, the average rate of narrowing of the joint gap in the pathologically altered knee joint in the doxycycline-treated group showed a 40% slower process than in the control group, and after 30 months — By 33%. At the same time, despite the significant slowing of the progression of the disease doxycycline had no effect on the severity of joint pain, although, as the authors of the study note, before starting treatment with doxycycline this index was low enough in both groups to be able to reliably judge about its change.

On the other hand, those taking this medication reported an increase in pain severity of 20% or more less compared to the severity of pain noted at their previous visit to the doctor. The incidence of narrowing of the articular cleft in patients in both groups, who noted an increase in the severity of pain, was 2 or more times higher than in those patients in whom the severity of the pain syndrome remained unchanged significantly. The researchers attributed this to the fact that joint pain — sign of synovitis leading to destruction of the joint. It should be noted that doxycycline was found to have no significant effect on the process of narrowing of the joint gap or the severity of pain in a relatively healthy joint. No more than 5% of the women tested reported side effects. In general, doxycycline was well tolerated by patients. In addition, those who received it noted the additional benefit of reduced incidence of urinary and upper respiratory tract infections.

As noted by the authors summarizing the results of this study, doxycycline has an inhibitory effect on the process of narrowing of the joint gap in already developed osteoarthritis. However, only further research can determine the role and place of this drug in the complex of therapeutic measures for this disease.