Azathioprine (Imuran)

Azathioprine is a treatment that has been used as a disease modifying drug in multiple sclerosis. Research suggests that its efficacy could be similar to that of the beta interferon drugs, however because of its side effect profile it is usually reserved for people with moderately aggressive disease. It is not one of the standard disease modifying drugs used in the UK.

A small study of people who did not respond to treatment with either beta interferon 1a or azathioprine alone, found a combination therapy was well tolerated and after two years of treatment no serious side effects were reported. Mean number of relapses over the trial period was significantly lower than before the combined treatment.

How azathioprine works

Azathioprine is an immunosuppressant drug used to prevent the rejection of transplanted organs, in the treatment of some cancers and also in the treatment of conditions such rheumatoid arthritis, lupus and hepatitis. In MS, studies suggest that azathioprine reduces relapse rate and slows down disability progression.

How azathioprine is taken

Azathioprine is normally taken as tablets (pills).

Side effects

Although generally well tolerated, side effects can include:

  • severe nausea
  • severe anaemia or leucopenia (a decrease in the number of white blood cells in the blood)
  • liver damage

Your doctors will monitor your blood cells and liver function during treatment. There is also an increased risk of developing cancer if azathioprine is taken long-term, though short-term use (less than five years) is not associated with a significantly increased risk.

Find out more

Massacesi L, et al.
Azathioprine versus beta interferons for relapsing-remitting multiple sclerosis: a multicentre randomized non-inferiority trial.
PLoS One 2014; 9(11): e113371.
Full article (link is external)
Casetta I, et al.
Azathioprine for multiple sclerosis.
Cochrane Database of Systematic Reviews 2007;(4):CD003982.
Full article (link is external)
Lus G, et al.
Azathioprine and interferon beta (1a) in relapsing-remitting multiple sclerosis patients: increasing efficacy of combined treatment.
European Neurology 2004;51(1):15-20.
Full article (link is external)
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