Mild upset stomach or flushing may occur. These effects are usually temporary and may disappear as your body adjusts to this product. If any of these effects last or get worse, tell your doctor or pharmacist promptly. If your doctor has directed you to use this medication, remember that 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. 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: altretamine, cisplatin, certain antibiotics (such as chloramphenicol), certain anti-seizure drugs (such as phenytoin), levodopa, other vitamin/nutritional supplements. This product may interfere with certain lab tests (such as urobilinogen, intrinsic factor antibodies), possibly causing false test results. Make sure lab personnel and all your doctors know you use this product.