Gas or stomach cramping may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly. If your doctor has directed you to use this product, 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. This product must be taken with at least a full glass of water or other liquid (8 ounces/240 milliliters) so that it will not swell in the throat, causing choking. Get medical help right away if after taking this product you have symptoms of choking such as: chest pain, vomiting, difficulty swallowing/breathing. 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.