Imuran (Azathioprine)

Imuran (azathioprine) is an oral tablet medication that suppresses the immune system and can be used to treat systemic scleroderma. It also is used to prevent organ rejection after organ transplantation and to treat other autoimmune conditions such as rheumatoid arthritis and myasthenia gravis.

How Imuran works

Systemic scleroderma is marked by a widespread accumulation of scar tissue in the skin and internal organs such as the lungs, heart, kidneys, and digestive tract. An abnormally activated immune system is a key contributor to the disease process.

Imuran stops DNA from being produced properly, interrupting the formation of new cells. In systemic scleroderma, Imuran halts the multiplication of immune cells (such as T-cells and B-cells) and the production of autoantibodies that mistakenly attack the body’s own tissues and organs.

Imuran in clinical trials for systemic scleroderma

A randomized unblinded trial compared the effect of 2 mg/kg of daily cyclophosphamide to 2.5 mg/kg of daily Imuran, both taken for a year by patients with systemic scleroderma. The results showed that Imuran did not appear to confer improved clinical benefits. In fact, patients who received cyclophosphamide experienced superior improvements in skin symptoms and lung function compared to those who received Imuran.

Meanwhile, some studies have supported the use of Imuran as a maintenance therapy after first receiving cyclophosphamide. One clinical study found that Imuran taken as 100 mg oral doses for a year was able to maintain improvements in skin symptoms and overall disease severity in patients who initially underwent a year of cyclophosphamide as injections directly into the bloodstream.

Another study, in which Imuran was taken by mouth for one-and-a-half years by patients who previously received six months of cyclophosphamide, found this regimen was able to maintain or improve lung function in patients with systemic scleroderma.

Current guidelines recommend the use of Imuran in systemic scleroderma patients who have received previous cyclophosphamide treatment to maintain improvements in skin symptoms and lung function.

More details about Imuran

Taking Imuran sometimes allows patients to lower the dose of corticosteroids they were originally prescribed. Imuran needs to be taken consistently for a few weeks or months before any improvements in symptoms become apparent.

Common side effects of Imuran include mild stomach upset, nausea, diarrhea, loss of appetite, hair loss, or skin rash. In addition, the use of Imuran increases the risk of some cancers, especially skin cancer and lymphoma.


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