Matrix metalloproteinases are involved in the pathogenesis of tendinopathy. Doxycycline, a
widely available pharmaceutical agent mostly used for its antibiotic properties, also
functions as an inhibitor of MMPs.
This study aims to investigate the effect of doxycycline treatment on lateral epicondylalgia
(tennis elbow). During three weeks, patients receive doxycycline tablets 100 mg twice daily,
or placebo. Main outcome variable is pain (VAS) at three weeks.
Serum and/or plasma levels of matrix metalloproteinases and tissue inhibitors of
metalloproteinases are measured.