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Pentasa Side Effects

Generic Name: mesalamine

Note: This document contains side effect information about mesalamine. Some of the dosage forms listed on this page may not apply to the brand name Pentasa.

For the Consumer

Applies to mesalamine: oral capsule delayed release, oral capsule extended release, oral tablet delayed release

Other dosage forms:

Along with its needed effects, mesalamine (the active ingredient contained in Pentasa) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking mesalamine:

More Common

Less Common

  • Blurred vision
  • dizziness
  • fever
  • full or bloated feeling
  • headache (severe)
  • itching, skin rash
  • nervousness
  • pounding in the ears
  • pressure in the stomach
  • slow or fast heartbeat
  • stomach cramps (severe)
  • swelling of the abdominal or stomach area
  • unusual tiredness or weakness


  • Anxiety
  • back pain (severe)
  • blue or pale skin
  • chest pain, possibly moving to the left arm, neck, or shoulder
  • chills
  • nausea
  • vomiting
  • yellow eyes or skin

Incidence Not Known

  • Blistering, peeling, or loosening of the skin
  • bloody urine
  • change in the ability to see colors, especially blue or yellow
  • clay- colored stools
  • cough
  • dark urine
  • decreased frequency or amount of urine
  • diarrhea
  • general feeling of discomfort or illness
  • greatly increased frequency of urination or amount of urine
  • hair loss
  • headache
  • hives
  • increased blood pressure
  • increased thirst
  • joint or muscle pain
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals
  • loss of appetite
  • lower back or side pain
  • red skin lesions, often with a purple center
  • red, irritated eyes
  • sore throat
  • sores, ulcers, or white spots in the mouth or on the lips
  • stomach pain or tenderness
  • swelling of the feet or lower legs
  • swollen glands
  • thickening of bronchial secretions
  • troubled breathing
  • weight gain

Some side effects of mesalamine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More Common

  • Diarrhea (mild)
  • runny or stuffy nose
  • sneezing

Less Common

  • Acne
  • back pain
  • belching
  • difficulty with moving
  • excess air or gas in the stomach or bowels
  • hair loss or thinning of the hair
  • heartburn
  • indigestion
  • muscle stiffness
  • passing gas
  • stomach discomfort or upset

For Healthcare Professionals

Applies to mesalamine: compounding powder, oral capsule extended release, oral delayed release capsule, oral delayed release tablet, rectal enema, rectal kit, rectal suppository


The most common adverse events were headache, eructation, and aggravation of ulcerative colitis.[Ref]


Very common (10% or more): Eructation (up to 16%), ulcerative colitis aggravated (up to 15%)

Common (1% to 10%): Abdominal pain/cramps/discomfort, diarrhea, flatulence, nausea, gastroenteritis, gastrointestinal hemorrhage, rectal disorder, stool abnormalities (color or texture change), urinary frequency, dyspepsia, vomiting, bloating, rectal distension, pain on insertion of tip (enema formulation), hemorrhoids, rectal pain, colitis, constipation, abdominal distension

Uncommon (0.1% to 1%): Acute pancreatitis, melena (bloody diarrhea), rectal pain/soreness/burning, pancolitis, neonate diarrhea, anal discomfort, defecation urgency, colitis ulcer (proctitis ulcer), glossitis, rectal polyp, pancreatitis, application site irritation (rectal foam formulation), painful rectal tenesmus, rectal urgency

Rare (less than 0.1%): Increased amylase

Frequency not reported: Duodenal ulcer, dysphagia, esophageal ulcer, fecal incontinence, GI bleeding, mouth ulcer, oral candidiasis, rectal bleeding, rectal polyp, mild indigestion and cramping, bloody diarrhea, stomatitis, abdominal enlargement, lipase increase

Postmarketing reports: Frequent bowel movements, mucus stools, painful defecation, proctalgia, rectal discharge, stomach discomfort, gastritis, dry mouth, oral ulcers, perforated peptic ulcer, amylase increased[Ref]

Nervous system

Very common (10% or more): Headache (up to 24%)

Common (1% to 10%): Dizziness

Uncommon (0.1% to 1%): Paresthesia, peripheral neuropathy, somnolence, tremor,

Very rare (less than 0.01%): Vertigo

Frequency not reported: Neuropathy, mild disorientation

Postmarketing reports: Guillain-Barre syndrome, hypertonia, transverse myelitis, hyperesthesia, taste perversion, tinnitus[Ref]


Very common (10% or more): Pain (up to 14%)

Common (1% to 10%): Asthenia, fatigue, pyrexia, infection

Uncommon (0.1% to 1%): Ear pain, peripheral edema

Rare (less than 0.1%): Drug fever

Frequency not reported: Malaise, mesalamine-induced acute intolerance syndrome, plugged ears, adenovirus infection, aching, decreased body mass index,

Postmarketing reports: Medication residue, elevated alkaline phosphatase, elevated GGT, elevated LDH, ear congestion[Ref]


Very common (10% or more): Nasopharyngitis (up to 15%)

Common (1% to 10%): Upper respiratory tract infection, influenza like symptoms, rhinitis, cold/sore throat

Uncommon (0.1% to 1%): Allergic and fibrotic lung reactions, dyspnea, cough, bronchospasm, pleural effusion, alveolitis, pulmonary eosinophilia, lung infiltration, pneumonitis, pharyngolaryngeal pain

Very rare (less than 0.01%): Eosinophilic pneumonia

Frequency not reported: Hypersensitivity pneumonitis (including interstitial pneumonitis, allergic alveolitis, eosinophilic pneumonitis, stuffy head, interstitial pulmonary fibrosis, bronchiolitis obliterans, sinusitis

Postmarketing reports: Fibrosing alveolitis, asthma exacerbation, pleuritis, bronchitis[Ref]


Common (1% to 10%): Hypertension, vasodilation,

Uncommon (0.1% to 1%): Pericarditis, myocarditis, pericardial effusion, tachycardia, hypotension

Frequency not reported: Chest pain, T-wave abnormalities, Kawasaki-like syndrome[Ref]


Common (1% to 10%): Rash, alopecia, urticaria, pruritus, acne

Uncommon (0.1% to 1%): Lupus erythematosus syndrome, allergic exanthema, increased sweating, angioedema, Stevens-Johnson syndrome, face edema

Very rare (less than 0.01%): Reversible alopecia, bullous skin reactions including erythema multiforme

Frequency not reported: Dry skin, eczema, erythema nodosum, nail disorder, photosensitivity, lichen planus, ecchymosis

Postmarketing reports: Prurigo, erythema, psoriasis, pyoderma gangrenosum[Ref]


Common (1% to 10%): Back pain, arthralgia, leg/joint pain

Uncommon (0.1% to 1%): Myalgia, chills, myositis, arthritis

Frequency not reported: Leg cramps, lower back discomfort, muscle cramps, neck pain

Postmarketing reports: Joint disorder, rheumatoid arthritis[Ref]


Common (1% to 10%): Hepatic function abnormal, increased alanine aminotransferase

Uncommon (0.1% to 1%): Hepatitis, increased liver enzymes (transaminase activity), intrahepatic cholestasis, increased bilirubin

Very rare (less than 0.01%): Hepatotoxicity (including cirrhosis, hepatic failure), changes in liver function parameters

Frequency not reported: GGTP increase, SGOT increase, SGPT increase, sclerosing cholangitis, increased alkaline phosphatase

Postmarketing reports: Jaundice, cholestatic jaundice, liver necrosis, cholecystitis[Ref]


Common (1% to 10%): Anorexia

Frequency not reported: Thirst, edema

Postmarketing reports: Increased appetite, gout[Ref]


Common (1% to 10%): Vision abnormalities

Uncommon (0.1% to 1%): Conjunctivitis

Postmarketing reports: Blurred vision, eye pain[Ref]


Uncommon (0.1% to 1%): Acute or chronic interstitial nephritis, renal insufficiency, renal failure, nephrotoxicity

Very rare (less than 0.01%): Nephrotic syndrome, urine discoloration

Frequency not reported: Creatinine clearance decreased

Postmarketing reports: Minimal change nephropathy, elevated serum creatinine and BUN[Ref]


Uncommon (0.1% to 1%): Thrombocytopenia, aplastic anemia, hemolytic anemia, agranulocytosis, leukopenia, neutropenia, pancytopenia, platelet count decreased

Very rare (less than 0.01%): Eosinophilia (as part of an allergic reaction), anemia, bone marrow depression

Frequency not reported: Thrombocythemia

Postmarketing reports: Granulocytopenia, lymphadenopathy[Ref]


Uncommon (0.1% to 1%): Allergic reaction, anaphylactic reaction, drug reaction with eosinophilia and systemic symptoms (DRESS)

Frequency not reported: Anaphylactic shock, angioedema[Ref]


Uncommon (0.1% to 1%): Oligospermia (reversible), UTI/urinary burning

Frequency not reported: Albuminuria, amenorrhea, breast pain, hematuria, hypomenorrhea, menorrhagia, metrorrhagia, urinary frequency

Postmarketing reports: Dysuria, urinary urgency, epididymitis[Ref]


Uncommon (0.1% to 1%): Insomnia

Frequency not reported: Depression, anxiety, decreased libido

Postmarketing reports: Nervousness, confusion, emotional lability, confusion[Ref]


1. "Product Information. Rowasa product information (mesalamine)." Solvay Pharmaceuticals Inc, Marietta, GA.

2. "Product Information. Lialda (mesalamine (5-aminosalicylic acid))." Shire US Inc, Florence, KY.

3. "Product Information. Pentasa Product Information (mesalamine)." Hoechst Marion-Roussel Inc, Kansas City, MO.

4. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

5. "Product Information. Asacol product information (mesalamine)." Procter and Gamble Pharmaceuticals, Cincinnati, OH.

6. "Product Information. Apriso (mesalamine (5-aminosalicylic acid))." Salix Pharmaceuticals, Raleigh, NC.

7. "Product Information. Delzicol (mesalamine (5-aminosalicylic acid))." Warner Chilcott Laboratories, Rockaway, NJ.

8. Cerner Multum, Inc. "Australian Product Information." O 0

9. "Product Information. Canasa (mesalamine (5-aminosalicylic acid))." Axcan Scandipharm Inc, Birmingham, AL.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.