Azathioprine (Imuran®)

What is Azathioprine (Imuran®)?

Azathioprine is an anti-inflammatory agent used to treat rheumatoid arthritis and other inflammatory conditions. It works by suppressing the blood cells that cause inflammation. Azathioprine is used to reduce signs and symptoms of rheumatoid arthritis, such as joint swelling, pain, tiredness, and duration of morning stiffness. Azathioprine is commonly known by the brand name Imuran®.

How do I take it?

Azathioprine is available in 50 mg tablets. These should be taken with a meal to reduce stomach upsets. It may be prescribed as a single dose or to be taken twice a day. Your doctor may start you at a low dose, which will be increased over time until you feel better.

What else should I know?

It can take up to 8-12 weeks after you start taking azathioprine for you to see improvement in your arthritis. The most common side effect is nausea. Itchy rashes, a sore mouth or throat and mouth ulcers may occur. Blood work will have to be done every 4-8 weeks to monitor your blood counts. Azathioprine can cause mild liver irritation. Please tell your doctor if you have a history of any alcohol abuse, hepatitis, yellow jaundice, or liver disease. While on Azathioprine your doctor may limit your alcoholic beverage intake.

Azathioprine can suppress your immune system making you more susceptible to infection. Notify your doctor if you have signs or symptoms of an infection and avoid people with contagious diseases.

Azathioprine may cause birth defects in children of women taking this drug. If you are pregnant or considering having a child, discuss this with your doctor before beginning this medication. Use of an effective form of birth control is critical throughout the course of this treatment and for months after it is stopped. Breast-feeding while taking Azathioprine is not recommended.

What about other medications?

When you are taking azathioprine, it is very important that your doctors know if you are taking any other medicine. This includes prescription and non–prescription medicines as well as birth control pills, vitamins, and herbal supplements.

Allopurinol (a common gout medicine) may increase azathioprine’s levels in your body. Please tell your doctor if you are taking allopurinol so that the dose of azathioprine can be properly adjusted. Aminosalicylates (olsalazine, mesalamine, sulfasalazine) may interfere with azathioprine and should be discussed with your doctor before beginning treatment.

Updated: April 25, 2012

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