Antibiotics and Osteoarthritis: What Research Shows
Osteoarthritis is the most common form of arthritis. It's a disease that affects most people over the age of 65 to some degree. While the standard treatment is anti-inflammatory medications to relieve the joint pain and stiffness, there’s some evidence that an antibiotic called doxycycline can slow down the progression of the disease. In a 2005 study published in the journal Arthritis and Rheumatism, middle-aged overweight women with severe osteoarthritis of a knee took either 100 milligrams of doxycycline twice a day or a placebo pill for 30 months.
The results were encouraging. This group of patients were followed for a full thirty months with x-rays and clinical exams. At 16 months, x-rays showed 40% less arthritis progression in the women who took doxycycline compared to the placebo group. Slowing of disease progression continued to be seen after 30 months on doxycycline.
The discouraging news was that even though there was less joint space narrowing and progression after the doxycycline treatment, the women didn’t experience reduced pain, although they were less likely to report increases in joint pain over time.
What conclusion can you draw from this? There’s no convincing evidence that antibiotics help arthritis pain in people with osteoarthritis, although they may slow down progression of the disease, which could reduce the need for joint replacements. There’s also the issue of side effects. Doxycycline was well-tolerated in this study, but the effects of taking it long-term aren’t clear. Antibiotics destroy good bacteria in the intestines that keep the digestive tract and immune system healthy. Some studies also show that antibiotics are associated with a higher risk of breast cancer.
How do antibiotics help arthritis? Researchers believe that antibiotics suppress enzymes and proteins that cause inflammation. In a sense, antibiotics have anti-inflammatory effects that slow down the progression of the disease.