What is Azathioprine (Imuran®)?
Azathioprine is an anti-inflammatory medicine 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. The dose is usually one to two tablets each day taken once or on a twice-daily schedule. Your doctor may start you at a low dose, which will be increased over time until you feel better. These should be taken with a meal to reduce upset stomach.
What about side effects?
The most common side effect is nausea and vomiting. This may improve over time, and can get better when the drug is taken after meals or in divided doses.
Itchy rashes, a sore mouth or throat and mouth ulcers may occur. Azathioprine may also irritate the liver.
Azathioprine can lower your immune system and increase your risk of getting infections. Notify your doctor if you have signs or symptoms of an infection and avoid people with contagious diseases.
Azathioprine may cause a decrease in your blood count, such as white blood cells and platelets. Very rarely, azathioprine may cause myelosuppression, which is when the blood cell counts become so low that it may lead to bleeding or severe infection. Your doctor may want to do a test (TPMT testing) to find out if you are at risk for this side effect.
Azathioprine may cause birth defects in children of women taking this drug.
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.
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.
Blood work will have to be done every 4-8 weeks to monitor your blood counts.
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. Your doctor may also want to check your blood to make sure you do not have Hepatitis B or C
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.