Adult:

Ulcerative Colitis (active, mild to moderate) --------> 0.5-1 G PO TDS for 8 weeks

Ulcerative Colitis(Remission maintenance) --------> 500 MG PO TDS for up to 8 weeks

Crohn Disease (Off-label) --------> 0.5-1 G PO 3 TDS for 8 weeks
Side effects:
abdominal pain, flulike syndrome, headache, gas (flatulence), nausea, fatigue, weakness, fever, dizziness, rash, severe itching, acne, sore throat, sensitivity reaction, cholestatic hepatitis, decreased creatinine clearance, liver failure, kidney impairment, vomiting, abdominal distension, diarrhea, joint pain, hives, hair loss, high blood pressure.
Drug interactions:

Serious interactions of mesalamine are:

antiacids (e.g., aluminum hydroxide, calcium carbonate, sodium bicarbonate)

H2 antagonists (e.g., cimetidine, famotidine, ranitidine)

actulose

non-steroidal anti-inflammatory drugs (NSAIDs; e.g., naproxen, ibuprofen)

warfarin

Azathioprine or 6-mercaptopurine

Alcohol (Alcohol can irritate stomach and intestines).