Azathioprine is an immunosuppressive medication. It is used to treat systemic lupus erythematosus, other autoimmune conditions and  less often an inflammatory arthritis.

It works by stabilizing and suppressing activated immune system.

It is available in 50 mg tablets and its usual dose is between 100 to 200 mg a day. It is given once or twice per day.

Azathioprine is contraindicated in breastfeeding women and in men and women trying to get pregnant. Sometimes it is given to pregnant women when benefits being on the medication overweight the risks.

It is not given to patients with chronic infections, liver, kidney and blood disorders.

Azathioprine starts working slowly, after 8-12 weeks being on it. The maximum effect can take up to 6 months.

Most of the medications used in rheumatology can be safely given with azathioprine. Allopurinol (gout medication) can interact with it and your doctor should know if you take it.

Common side effects of azathioprine are:

  • nausea (taken with food can help to decrease it), diarrhea;
  • aching of the joints;
  • rash.

Rare side effects include:

  • elevation of the liver enzimes and decrease in cell counts (this is why it is important to do regular blood work while being on this medication);
  • fevers and feeling unwell;
  • when taken for prolong period of time, it can give a small increase in the risk of the blood cancers;
  • any fever or infection developed while being on this medication should be taken seriously (notify your doctor).

Your pharmacist will give you the full list of the side effects when you buy the medication. Please, advise your pharmacist about other medications you take.