Doxycycline is an antibiotic drug.  It is used to treat a range of infections including pneumonia, acne and chlamydia.  Two small trials have explored whether it has an effect on reducing activity in the immune system in MS.

A laboratory based trial looked at the effect of doxycycline on a number of conditions in children.  This included 11 samples from children with MS.

A second trial involved 15 people with relapsing remitting MS who took both interferon beta 1a and doxycycline for four months. Results suggest that using the two drugs together may reduce the number of areas of disease activity shown by MRI scans.

Both trials were too small to give very clear answers.  Doxycycline has not yet been tested in larger studies.

Find out more

Anlar B, et al.
Doxycycline in autoimmune central nervous system disorders in children: an in vitro study.
Turkish Journal of Pediatrics 2007;49(3):274-277.
Summary (link is external)
Minagar A, et al.
Combination therapy with interferon beta-1a and doxycycline in multiple sclerosis: an open-label trial.
Archives of Neurology 2008;65(2):199-204.
Full article (link is external)