- What is azathioprine, and how does it work (mechanism of action)?
- What are the side effects of azathioprine?
- What is the dosage for azathioprine?
- Which drugs or supplements interact with azathioprine?
- Is azathioprine safe to take if I'm pregnant or breastfeeding?
- What else should I know about azathioprine?
What is azathioprine, and how does it work (mechanism of action)?
Azathioprine is an immunosuppressant, that is, a drug that is used to suppress the immune system. It is used to treat patients who have undergone kidney transplantation and for diseases in which modifying the activity of the immune system is important. Azathioprine is a prodrug (a precursor of a drug) which is converted in the body to its active form called mercaptopurine (Purinethol). The exact mechanism of action of azathioprine is not known.
Like other immunosuppressants, it suppresses the proliferation of T and B lymphocytes, types of white blood cells that are part of the immune system and defend the body against both infectious diseases and foreign materials. For example, in the case of organ transplantation, immunosuppressants prevent the body from immunologically rejecting the new organ. In the case of autoimmune diseases (diseases caused by an abnormal immune reaction against the body's own tissues) such as rheumatoid arthritis, suppressing the immune system reduces the inflammation that accompanies immune reactions and slows damage to the joints caused by the inflammation. The FDA approved azathioprine in March 1968.
What brand names are available for azathioprine?
Is azathioprine available as a generic drug?
Do I need a prescription for azathioprine?
What are the side effects of azathioprine?
The most common serious side effects of azathioprine involve the cells of the blood and gastrointestinal system. Azathioprine can cause serious lowering of the white blood cell count, resulting in an increased risk of infections. This effect is reversed when the dose of azathioprine is reduced or temporarily discontinued. Azathioprine can cause nausea, vomiting, and loss of appetite, which may resolve when the daily dose is reduced or divided and taken more than once a day. Azathioprine can cause liver toxicity (for example, in less than 1% of rheumatoid arthritis patients). All patients taking azathioprine require regular testing of blood for blood cell counts and liver tests to monitor for side effects of azathioprine. Other side effects encountered less frequently include fatigue, hair loss, joint pains, and diarrhea.
What is the dosage for azathioprine?
The initial dose for preventing organ rejection is 3 to 5 mg/kg (oral or IV) daily, starting at the time of transplantation or in some cases 1 to 3 days before transplantation. The initial off-label dose for treating rheumatoid arthritis is 1.0 mg/kg (50 to 100 mg, oral or IV) as a single dose or twice daily. Doses may be increased by 0.5 mg/kg daily up to a maximum dose of 2.5 mg/kg per day. Dosing for other off-label use may vary according to what disease is being treated; in general, off-label use should be done by an experienced medical specialist. Azathioprine should be taken with food.
Which drugs or supplements interact with azathioprine?
Allopurinol (Zyloprim) that is used for treating increased blood levels of uric acid and preventing gout increases azathioprine levels in the blood which may increase the risk of side effects from azathioprine. Therefore, it is important to reduce the dose of azathioprine by approximately 1/3 to 1/4 in patients taking allopurinol. The use of angiotensin-converting enzyme (ACE) inhibitors to control high blood pressure in patients taking azathioprine has been reported to induce anemia (low levels of red blood cells) and severe leukopenia (low levels of white blood cells). Azathioprine reduces blood levels of the blood thinner, warfarin (Coumadin), and thus may reduce the blood thinning effect of warfarin.
Is azathioprine safe to take if I'm pregnant or breastfeeding?
Azathioprine can cause fetal harm when given to pregnant women and whenever possible should be avoided.
Azathioprine is found in breast milk and should not be used in nursing mothers.
What else should I know about azathioprine?
What preparations of azathioprine are available?
Tablet: 25, 50, 75, 100 mg. Injection: 100 mg
How should I keep azathioprine stored?
Azathioprine should be stored at 15 C -25 C (59 F -77 F) in a dry place and protected from light.
Azathioprine (Imuran, Azasan) is a drug prescribed for prevention of organ rejection in kidney transplants. Off label uses for azathioprine (Imuran, Azasan) include rheumatoid arthritis, multiple sclerosis, Crohn's disease, myasthenia gravis, ulcerative colitis, and autoimmune hepatitis. Side effects, drug interactions, and safety during pregnancy information should be reviewed prior to taking this drug.
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Related Disease Conditions
Rheumatoid Arthritis (RA)
Rheumatoid arthritis (RA) is an autoimmune disease that causes chronic inflammation of the joints, the tissue around the joints, as well as other organs in the body. Early RA signs and symptoms include anemia, both sides of the body affected (symmetric), depression, fatigue, fever, joint deformity, joint pain, joint redness, joint stiffness, joint swelling, joint tenderness, joint warmth, limping, loss of joint function, loss of joint range of motion, and polyarthritis.
Multiple Sclerosis (MS)
Multiple sclerosis or MS is an autoimmune disorder in which brain and spinal cord nerve cells become demyelinated. This damage results in symptoms that may include numbness, weakness, vertigo, paralysis, and involuntary muscle contractions. Different forms of MS can follow variable courses from relatively benign to life-threatening. MS is treated with disease-modifying therapies. Some MS symptoms can be treated with medications.
Lupus (Systemic Lupus Erythematosus or SLE)
Systemic lupus erythematosus is a condition characterized by chronic inflammation of body tissues caused by autoimmune disease. Lupus can cause disease of the skin, heart, lungs, kidneys, joints, and nervous system. When only the skin is involved, the condition is called discoid lupus. When internal organs are involved, the condition is called systemic lupus erythematosus (SLE).
Pulmonary fibrosis is scarring throughout the lungs. Pulmonary fibrosis can be caused by many conditions including chronic inflammatory processes, infections, environmental agents, exposure to ionizing radiation, chronic conditions, and certain medications. Symptoms include shortness of breath, coughing, and diminished exercise tolerance. Treatment options are dependent on the type of pulmonary fibrosis; lung transplant and/or medications are options.
Ulcerative colitis is a chronic inflammation of the colon. Symptoms and signs include abdominal pain, diarrhea, and rectal bleeding. Ulcerative colitis is closely related to Crohn's disease, and together they are referred to as inflammatory bowel disease. Treatment depends upon the type of ulcerative colitis diagnosed.
Sjögren's syndrome is an autoimmune disease involving the abnormal production of extra antibodies that attack the glands and connective tissue. It is also associated with a connective tissue disease, such as rheumatoid arthritis, systemic lupus erythematosus, or scleroderma, which is referred to as secondary Sjögren's syndrome. Though there is no cure for Sjögren's syndrome, the symptoms may be treated by using lubricating eye ointments, drinking plenty of water, humidifying the air, and using glycerin swabs. Medications are also available to treat dry eye and dry mouth.
Celiac disease is a condition in which a person has inflammation of the small intestinal mucosa when exposed to gluten in the diet. Symptoms of celiac disease include bloating, nausea, diarrhea, and abdominal discomfort. Treatment involves following a gluten-free diet. Some individuals may have refractory celiac disease in which they do not respond to a gluten-free diet.
Scleritis is inflammation of the white part of the eye. It may be caused by a serious underlying condition, such as an autoimmune disease. Symptoms include redness, pain, tearing, sensitivity to light, and decreased visual acuity. Treatment may include eyedrops as well as treatment for any underlying disease process. Scleritis cannot be prevented.
Inflammatory Bowel Disease (IBD)
The inflammatory bowel diseases (IBD) are Crohn's disease (CD) and ulcerative colitis (UC). The intestinal complications of Crohn's disease and ulcerative colitis differ because of the characteristically dissimilar behaviors of the intestinal inflammation in these two diseases.
Sarcoidosis, a disease resulting from chronic inflammation, causes small lumps (granulomas) to develop in a wide range of body tissues and can appear in almost any body organ. However, sarcoidosis most often starts in the lungs or lymph nodes.
Polymyositis and Dermatomyositis
Polymyositis is a disease of the muscle featuring inflammation of the muscle fibers. It results in weakness of the muscles which can be severe and when associated with skin rash, is referred to as dermatomyositis. Although the cause of this disease is unknown, diagnosis includes physical examination of muscle strength, blood tests for muscle enzymes, electrical tests of muscle and nerves, and conformation by a muscle biopsy. Treatment of polymyositis and dermatomyositis includes high doses of cortisone-related medications, immune suppression, and physical therapy.
Scleroderma is an autoimmune disease of the connective tissue. It is characterized by the formation of scar tissue (fibrosis) in the skin and organs of the body, leading to thickness and firmness of involved areas. Scleroderma is also referred to as systemic sclerosis, and the cause is unknown. Treatment of scleroderma is directed toward the individual features that are most troubling to the patient.
Crohn's Disease vs. Ulcerative Colitis
Crohn's disease and ulcerative colitis are diseases that cause inflammation of part of or the entire digestive tract (GI). Crohn's affects the entire GI tract (from the mouth to the anus), while ulcerative colitis or ulcerative colitis only affects the large and small intestine and ilium. Researchers do not know the exact cause of either disease. About 20% of people with Crohn's disease also have a family member with the disease. Researchers believe that certain factors may play a role in causing UC. Both Crohn's disease and ulcerative colitis are a type of inflammatory bowel disease or IBD. Crohn's disease and ulcerative colitis both have similar symptoms and signs, for example, nausea, loss of appetite, fatigue, weight loss, episodic and/or persistent diarrhea, fever, abdominal pain and cramping, rectal bleeding, bloody stools, joint pain and soreness, eye redness, or pain. Symptoms unique to Crohn’s disease include anemia and skin changes. Symptoms of unique to ulcerative colitis include certain rashes, and an urgency to defecate (have a bowel movement). Doctors diagnose both diseases with similar tests and procedures. While there is no cure for either disease, doctors and other health care professionals can help you treat disease flares, and manage your Crohn's or ulcerative colitis with medication, diet, nutritional supplements, and/or surgery.
Vasculitis (arteritis, angiitis) is a general term for a group of uncommon diseases which feature inflammation of the blood vessels. Each form of vasculitis has its own characteristic pattern of symptoms. The diagnosis of vasculitis is definitively established after a biopsy of involved tissue demonstrates the pattern of blood vessel inflammation. Treatment is directed toward decreasing the inflammation of the arteries and improving the function of affected organs.
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IBS vs. IBD: Differences and Similarities
IBS (irritable bowel syndrome) and IBD (inflammatory bowel disease) are both problems with the digestive tract (gastrointestinal or GI tract), but they are not the same disease. Check out the center below for more medical references on IBS and IBD, including multimedia (slideshows, images, and quizzes), related disease conditions, treatment and diagnosis, medications, and prevention or wellness.
Mixed Connective Tissue Disease (MCTD)
Connective tissue diseases are disorders featuring abnormalities involving the collagen and elastin. Connective tissue diseases that are strictly inheritable include Marfan syndrome and Ehlers-Danlos syndrome. The classic immune-related connective tissue diseases include systemic lupus erythematosus, rheumatoid arthritis, scleroderma, polymyositis, and dermatomyositis. Treatment is often directed at suppressing the inflammation present in the tissues by using anti-inflammatory and immunosuppressive medications.
Henoch-Schonlein Purpura (HSP)
Henoch-Schonlein purpura (HSP or anaphylactoid purpura), a type of blood vessel inflammation, results in rash, arthritis, and occasional abdominal cramping. HSP often resolves on its own. Joint pain may be treated with anti-inflammatory and cortisone medications.
Interstitial Lung Disease (Interstitial Pneumonia)
Interstitial lung disease refers to a variety of diseased that thicken the tissue between the lungs' air sacks. Symptoms of interstitial lung disease include shortness of breath, cough, and vascular problems, and their treatment depends on the underlying cause of the tissue thickening. Causes include viruses, bacteria, tobacco smoke, environmental factors, cancer, and heart or kidney failure.
Primary Biliary Cirrhosis (PBC)
Primary Biliary Cirrhosis (PBS) is a liver disease in which bile building up in the organ damages bile ducts. Ultimately, this can cause liver failure. A number of drugs are available to treat this disease of unknown cause, but the only ultimate cure is a liver transplant.
Optic neuritis is inflammation of the optic nerve, the structure that connects the eye to the brain. The precise cause of optic neuritis is unknown, but it is thought to be a type of autoimmune disorder. Optic neuritis most commonly develops due to an autoimmune disorder that may be triggered by a viral infection.
Relapsing polychondritis is an uncommon, chronic disorder of the cartilage that is characterized by recurrent episodes of inflammation of the cartilage of various tissues of the body. Tissues containing cartilage that can become inflamed include the ears, nose, joints, spine, and windpipe (trachea). Tissues that have a biochemical makeup similar to that of cartilage such as the eyes, heart, and blood vessels, can also be affected. Nonsteroidal anti-inflammatory medications (NSAIDs) is used as treatment for mild cases of the disease. Steroid-related medications also are usually required.
Microscopic Colitis (Lymphocytic Colitis and Collagenous Colitis)
Microscopic colitis (lymphocytic colitis and collagenous colitis) is a disease of inflammation of the colon. Microscopic colitis is only visible when the colon's lining is examined under a microscope. The cause of microscopic colitis is not known. Symptoms of microscopic colitis are chronic watery diarrhea and abdominal pain or cramps.
Still's disease is a disorder characterized by inflammation with high fever spikes, fatigue, salmon-colored rash, and/or arthritis. Though there have been several theories regarding the cause(s) of Still's disease, the cause is not yet known. Many symptoms of Still's disease are often treatable with anti-inflammatory drugs.
Polyarteritis nodosa is a rare autoimmune disease characterized by spontaneous inflammation of the arteries of the body. The most common areas of involvement include the muscles, joints, intestines (bowels), nerves, kidneys, and skin. Poor function or pain in any of these organs can be a symptom. Polyarteritis nodosa is most common in middle age persons. Polyarteritis is a serious illness that can be fatal. Treatment is focused on decreasing the inflammation of the arteries by suppressing the immune system.
What Is Weber-Christian Disease?
Weber-Christian disease is a rare inflammatory disease that affects the body's fat tissues. The disorder appears on the skin as red or purple tender, raised lumps usually on the thighs and lower legs. Other symptoms may include nausea, vomiting, weight loss, joint pain, and abdominal pain. There is no cure for the disease, but anti-inflammatory medications may help with inflammation.
Bullous pemphigoid is a skin disease that causes blistering eruptions on the skin's surface and sometimes affects the inner lining of the mouth. Symptoms include severe itching and burning sensations. Treatment involves topical cortisone and sometimes high doses of cortisone. Severe cases may require immune-suppression drugs such as azathioprine.
Primary Biliary Cirrhosis (PBC) Treatment
Primary biliary cirrhosis (PBC) is thought to be an autoimmune disorder that involves the deterioration of the liver's small bile ducts. These ducts are crucial to transport bile to the small intestine, digesting fats and removing wastes. Symptoms of PBC are edema, itching, elevated cholesterol, malabsorption of fat, liver cancer, gallstones, urinary tract infections (UTIs), and hypothyroidism. Treatments include ursodeoxycholic acid (UDCA); colchicine (Colcrys); and immunosuppressive medications, such as corticosteroids; obeticholic acid (Ocaliva); and medications that treat PBC symptoms. For PBC that is associated with cirrhosis of the liver, liver transplantation may be indicated in extreme cases.
Granulomatosis With Polyangiitis
Granulomatosis with polyangiitis is a condition that usually affects young or middle-aged adults, is an inflammation of the arteries supplying blood to the sinuses, lungs, and kidneys. Symptoms of granulomatosis with polyangiitis include bloody sputum, fatigue, weight loss, joint pain, sinusitis, shortness of breath, and fever. Granulomatosis with polyangiitis may be fatal within months without treatment. Treatment aims to stop inflammation with high doses of prednisone and cyclophosphamide.
Juvenile Rheumatoid Arthritis (JRA)
Juvenile rheumatoid arthritis (JRA) annually affects one child in every thousand. There are six types of JRA. Treatment of juvenile arthritis depends upon the type the child has and should focus on treating the symptoms that manifest.
Takayasu disease (also referred to as Takayasu arteritis) is a chronic inflammation of the aorta and its branch arteries. Takayasu disease is most common in women of Asian descent and usually begins between 10-30 years of age. Symptoms include painful extremities, dizziness, headaches, chest and abdominal pain, and a low-grade fever. Treatment for Takayasu disease includes cortisone medication to suppress the inflammation.
Essential Mixed Cryoglobulinemia
Essential mixed cryoglobulinemia is a condition caused by abnormal blood proteins called cryoglobulins. Symptoms include joint pain, swelling, skin vasculitis, enlarged spleen, and nerve and kidney disease. Treatment involves medications that reduce inflammation and suppress the immune system.
Felty's syndrome is a complication of long-term rheumatoid arthritis. Felty's syndrome is defined by the presence of three conditions: rheumatoid arthritis, an enlarged spleen, and an abnormally low white blood count. Treatment of Felty's syndrome is not always required; however, treatment for patients with infections is available.
Treatment & Diagnosis
- Rheumatoid Arthritis (RA)
- Systemic Lupus Erythematosus (SLE)
- Myasthenia Gravis
- Lymphocytic Colitis
- Ulcerative Colitis
- Polyarteritis Nodosa (PAN)
- Henoch-Schonlein Purpura
- Inflammatory Bowel Disease
- Sjogren's Syndrome
- Pulmonary Fibrosis
- Crohn's Disease
- Bullous Pemphigoid
- Doctor: Checklist to Take To Your Doctor's Appointment
- Juvenile Idiopathic Arthritis
- Still's Disease
- Granulomatosis With Polyangiitis (GPA)
- Weber-Christian Disease
- Hypersensitivity Pneumonitis
- Interstitial Lung Disease
- Rheumatoid Arthritis FAQs
- Celiac Disease Celiac Sprue FAQs
- Ulcerative Colitis FAQs
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- Lupus Nephritis Treatment
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- Indications for Drugs: Approved vs. Non-approved
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- Pharmacy Visit, How To Get The Most Out of Your Visit
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