What Is Mesalamine and How Does It Work?

Mesalamine is a prescription drug indicated for the induction of remission in patients with active, mild to moderate ulcerative colitis, and for the maintenance of remission of ulcerative colitis.

What Are Dosages of Mesalamine?

Dosages of Mesalamine:

Capsule, extended-release

  • 250 mg (Pentasa)
  • 375 mg (Apriso)
  • 500 mg (Pentasa)

Tablet, delayed-release


  • 400 mg (Asacol)
  • 800 mg (Asacol HD)
  • 1.2 g (Lialda)


  • 400 mg (Asacol)

Capsule, delayed-release

Adult and Pediatric

  • 400 mg (Delizicol)

Dosage Considerations – Should be Given as Follows:

Ulcerative Colitis


Remission induction of active, mild to moderate disease

  • Asacol HD: 1.6 g orally three times daily
  • Delzicol: 800 mg orally three times daily 1 hour before eating or 2 hours after eating
  • Lialda: 2.4-4.8 g orally each day with meal up to 8 weeks
  • Pentasa: 1 g orally four times daily for 8 weeks

Remission maintenance

  • Apriso: 1.5 g orally once per day in the morning
  • Delzicol: 1.6 g/day orally in divided doses 1 hour before eating or 2 hours after eating
  • Asacol: 1.6 g/day orally in divided doses 1 hour before eating or 2 hours after eating
  • Lialda: 2.4 g orally each day with food
  • Pentasa: 1 g/day orally four times daily for up to 8 weeks


  • Children under 5 years of age: safety and efficacy not established
  • Asacol or Delzicol: indicated for mildly to moderately active ulcerative colitis in children aged over 5 years
  • Duration of treatment: 6 weeks
    • Children 17 kg to less than 33 kg: 36-71 mg/kg/day orally divided twice daily; not to exceed 1.2 g/day
    • Children 33 kg to less than 54 kg: 37-61 mg/kg/day orally divided twice daily; not to exceed 2 g/day
    • Children 54 kg to 90 kg: 27-44 mg/kg/day orally divided twice daily; not to exceed 2.4 g/day

Crohn Disease (off-label)

Remission induction of active, mild-to-moderate disease

  • Asacol HD: 1.6 g three times daily
  • Lialda: 2.4-4.8 g orally each day with food for up to 8 weeks
  • Pentasa: 1 g orally four times daily for 8 weeks

What Are Side Effects Associated with Using Mesalamine?

Side effects of mesalamine include:

  • abdominal pain
  • abdominal discomfort
  • headache
  • gas (flatulence)
  • nausea
  • fatigue
  • a general feeling of discomfort
  • weakness
  • fever
  • worsening of colitis
  • dizziness
  • rash
  • severe itching
  • acne
  • sore throat
  • sensitivity reaction
  • cholestatic hepatitis
  • decreased creatinine clearance
  • flulike syndrome
  • discolored urine
  • kidney impairment
  • mesalamine-induced acute intolerance syndrome
  • hypersensitivity reactions
  • liver failure
  • inflammatory bowel disease
  • abnormal liver function test
  • diarrhea
  • abdominal distension
  • upper abdominal pain
  • indigestion
  • back pain
  • joint pain
  • high blood pressure
  • hair loss
  • hives
  • pancreatitis
  • rectal polyps
  • vomiting
  • fever
  • ear pain

Rare side effects of mesalamine include:

  • inflammation around the heart

Postmarketing side effects of mesalamine reported include:

  • Body as a whole: Lupus-like syndrome, drug fever
  • Cardiac disorders: inflammation around the heart, fluid around the heart, inflammation of the heart muscle
  • Gastrointestinal: Pancreatitis, inflammation of the gall bladder, gastritis, gastroenteritis, gastrointestinal bleeding, perforated peptic ulcer
  • Hepatic: Yellowing skin and eyes (jaundice), cholestatic jaundice, hepatitis, liver necrosis, liver failure, Kawasaki-like syndrome including changes in liver enzymes
  • Hematologic: lowered white blood cell count, damage to the stem cells that makes blood cells (aplastic anemia)
  • Immune system disorders: severe allergic reaction, Stevens-Johnson syndrome (SJS), drug reaction with eosinophilia and systemic symptoms (DRESS), swelling of the skin
  • Musculoskeletal and connective tissue disorders: muscle pain
  • Neurological/psychiatric: numbness and pain in your hands and feet, Guillain-Barre syndrome, inflammation of both sides of one section of the spinal cord
  • Renal disorders: inflammation in the kidney, kidney failure, kidney disease where protein leaks in the urine (minimal change nephropathy)
  • Respiratory, thoracic, and mediastinal disorders: Hypersensitivity pneumonitis (including sudden shortness of breath, allergic inflammation of the lungs, high white blood cell count in the lungs)
  • Skin: Psoriasis, open sores usually on the legs (pyoderma gangrenosum), red tender lumps most commonly on the legs
  • Urogenital: reversible low concentration of sperm

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

What Other Drugs Interact with Mesalamine?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

Mesalamine has no known severe interactions with other drugs.

Serious interactions of mesalamine include:

Mesalamine has moderate interactions with at least 48 different drugs.

Mesalamine has mild interactions with at least 94 different drugs.

This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns, or for more information about this medicine.

What Are Warnings and Precautions for Mesalamine?


This medication contains mesalamine. Do not take Asacol HD, Pentasa, Delzicol, Lialda, or Apriso if you are allergic to mesalamine or any ingredients contained in this drug.

Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately


  • Hypersensitivity to mesalamine or salicylates
  • Breastfeeding
  • Rectal suspension: hypersensitivity to salicylates, aminosalicylates, or to any ingredients in the suppository vehicle
  • Children with chickenpox or flulike symptoms

Effects of Drug Abuse

  • No information available

Short-Term Effects

  • See "What Are Side Effects Associated with Using Mesalamine?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Mesalamine?"


  • Sulfasalazine hypersensitivity, renal insufficiency, coagulation abnormalities, pyloric stenosis
  • Use caution in active peptic ulcer disease, severe renal failure
  • Do not use with lactulose or drugs that lower intestinal pH
  • Although pericarditis rarely occurs, investigate any chest pain or shortness of breath
  • A low concentration of sperm has been reported in males
  • Liver failure may occur, particularly with preexisting liver impairment
  • May lead to falsely elevated test results when measuring urinary normetanephrine by liquid chromatography with electrochemical detection, because of the similarity in the chromatograms of normetanephrine and mesalamine's main metabolite, N-acetyl aminosalicylic acid; an alternative, selective assay for normetanephrine should be considered
  • Worsening of colitis or inflammatory bowel disease may occur following initiation of therapy
  • Renal impairment, including minimal change nephropathy, acute, and chronic interstitial nephritis, and renal failure, reported; evaluate renal function prior to initiation of therapy and periodically while on therapy
  • Evaluate the risks and benefits in patients with known renal impairment or taking nephrotoxic drugs; monitor renal function
  • Acute intolerance syndrome may occur; symptoms may be difficult to distinguish from an ulcerative colitis exacerbation; monitor for worsening symptoms; discontinue if acute intolerance syndrome suspected
  • Hypersensitivity reactions, including myocarditis and pericarditis, reported; evaluate patients immediately and discontinue if hypersensitivity reaction suspected
  • Evaluate the risks and benefits in patients with known liver impairment

Pregnancy and Lactation

  • Use mesalamine during pregnancy with caution if benefits outweigh risks
  • Animal studies show risk and human studies are not available, or neither animal nor human studies were done
  • Effects of mesalamine during pregnancy are unknown
  • It is reported to cross the placental barrier and appear in cord blood; increased congenital malformations, primarily spina bifida and cleft palate reported in offspring of rodents given oral doses of 150-250 mg/kg/day during pregnancy; case reports of postnatal hemorrhage in mother and infant when administered during last few weeks of pregnancy
  • Mesalamine enters breast milk; consult with your physician if breastfeeding
Medscape. Mesalamine.
RxList. Lialda Monograph.

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