Osteoarthritis of the knee can cause significant disability. It causes pain, stiffness and limits movement. Besides the usual pain killers and anti-inflammatory drugs used to control the symptoms, a number of new drugs are being tried out that could modify the course of the disease itself and provide relief to the patient. These drugs are referred to as disease-modifying osteoarthritis drugs (DMOAD).
Doxycycline is one of the drugs being tried out to check if it qualifies for being a DMOAD. It belongs to the tetracycline group of antibiotics. Doxycycline is currently used for a number of bacterial and other infections. It has been found to inhibit metalloproteinase, an enzyme which contributes to degeneration of cartilage in the joints. Some prior studies have indicated that doxycycline may slow the progression of osteoarthritis.
AdvertisementA study was conducted in Netherlands to evaluate the effect of doxycycline on pain and daily functioning in patients with knee osteoarthritis. The patients received either doxycycline or a similar appearing inert drug called a placebo for 24 weeks.
The study found that 27% patients in the doxycycline group and 35% patients in the placebo group showed a response to treatment. This shows that doxycycline is not effective in reducing symptoms of pain, stiffness or improving function of the knee joint in patients with knee osteoarthritis. On the contrary, it was associated with more side effects. Discontinuation of treatment was more common in patients taking doxycycline as compared to those taking placebo.
Thus, doxycycline cannot be currently recommended to relieve symptoms in patients with knee osteoarthritis. Further research with synthetic metalloproteinase inhibitors that can improve symptoms in osteoarthritis without producing excessive adverse effects is warranted.
1. Gijs et al; The effects of doxycycline on reducing symptoms in knee osteoarthritis: results from a triple-blinded randomised controlled trial; Ann Rheum Dis 2011; doi:10.1136/ard.2010.147967