This medication usually has fewer side effects than other corticosteroids because budesonide works in the gut and only small amounts are absorbed into the body. Nausea, abdominal pain, or headache may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly. Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Because this drug works by weakening the immune system, it may lower your ability to fight infections. This may make you more likely to get a serious (rarely fatal) infection or make any infection you have worse. Tell your doctor right away if you have any signs of infection (such as sore throat that doesn't go away, fever, chills, cough). This medication may sometimes cause oral thrush or a new yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms. Tell your doctor right away if you have any serious side effects, including: easy bruising/bleeding, puffy face, unusual weight gain, menstrual period changes, mental/mood changes (such as depression, mood swings, agitation), muscle weakness/pain, bone pain, thinning skin, slow wound healing, increased thirst/urination, vision problems, symptoms of stomach/intestinal bleeding (such as stomach/abdominal pain, black/tarry stools, vomit that looks like coffee grounds), red/purple spots on the skin. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Some products that may interact with this drug are: aldesleukin, desmopressin, mifepristone, drugs that can cause bleeding/bruising (including antiplatelet drugs such as clopidogrel, "blood thinners" such as dabigatran/warfarin, NSAIDs such as aspirin/celecoxib/ibuprofen). If your doctor has told you to take low-dose aspirin to prevent heart attack or stroke (usually 81-162 milligrams a day), you should keep taking the aspirin unless your doctor tells you not to. Ask your doctor or pharmacist for more details. This product may interfere with certain lab tests (such as skin tests), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.