SIDE EFFECTS: Stomach upset, nausea/vomiting, constipation, headache, or joint/muscle pain may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly. You may sometimes see whole or partial tablets in your stool. If this happens often, tell your doctor. You may not be absorbing enough of the medication. Remember that your doctor has prescribed this medication because he or she 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. Infrequently, mesalamine can worsen ulcerative colitis. Tell your doctor right away if your symptoms worsen after starting this medication (such as increased abdominal pain/cramping, bloody diarrhea, fever). Tell your doctor right away if you have any serious side effects, including: signs of kidney problems (such as change in the amount of urine), dark urine, nausea/vomiting that doesn't stop, severe stomach/abdominal pain, yellowing eyes/skin, chest pain, shortness of breath. 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.

PRECAUTIONS: Before taking mesalamine, tell your doctor or pharmacist if you are allergic to it; or to other aminosalicylates (such as balsalazide, olsalazine); or to salicylates (such as aspirin, salsalate); or to sulfasalazine; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details. Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, liver disease, stomach blockage (such as pyloric stenosis), skin problems (such as atopic dermatitis, eczema). Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products). This medication is similar to aspirin. Children and teenagers younger than 18 years should not take aspirin or aspirin-related medications (such as salicylates) if they have chickenpox, flu, or any undiagnosed illness, or if they have recently received a vaccine. In these cases, taking mesalamine increases the risk of Reye's syndrome, a rare but serious illness. During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor. This medication passes into breast milk and may have undesirable effects on a nursing infant. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval. Mesalamine is very similar to balsalazide, olsalazine, and sulfasalazine. Do not use medications containing balsalazide, olsalazine, or sulfasalazine while using mesalamine. This medication may interfere with certain lab tests (such as urine normetanephrine levels), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.

OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: ringing in the ears, confusion, rapid breathing, seizures.