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Olsalazine has been evaluated in ulcerative colitis patients in remission, as well as those with acute disease. Both sulfasalazine-tolerant and intolerant patients have been studied in controlled clinical trials. Overall, 10.4% of patients discontinued olsalazine because of an adverse experience compared with 6.7% of placebo patients. The most commonly reported adverse reactions leading to treatment withdrawal were diarrhea or loose stools (olsalazine 5.9%; placebo 4.8%), abdominal pain, and rash or itching (slightly more than 1% of patients receiving olsalazine). Other adverse reactions to olsalazine leading to withdrawal occurred in fewer than 1% of patients (Table 1).

Table1: Adverse Reactions Resulting In Withdrawal From Controlled Studies Total

(N = 441)
(N = 208)
Diarrhea/Loose Stools 26 (5.9%) 10 (4.8%)
Nausea 3 2
Abdominal Pain 5 (1.1%) 0
Rash/Itching 5 (1.1%) 0
Headache 3 0
Heartburn 2 0
Rectal Bleeding 1 0
Insomnia 1 0
Dizziness 1 0
Anorexia 1 0
Light Headedness 1 0
Depression 1 0
Miscellaneous 4 (0.9%) 3 (1.4%)
Total Number of Patients Withdrawn 46 (10.4%) 14 (6.7%)

For those controlled studies, the comparative incidences of adverse reactions reported in 1% or more patients treated with olsalazine or placebo are provided in Table 2.

Table2: Comparative Incidence (%) of Adverse Effects Reported By One Percent Or More of Ulcerative Colitis Patients Treated With Olsalazine Or Placebo in Double Blind Controlled Studies

Adverse Event Olsalazine
Gastrointestinal Disorders
  Diarrhea 11.1 6.7
  Abdominal Pain/Cramps 10.1 7.2
  Nausea 5.0 3.9
  Dyspepsia 4.0 4.3
  Bloating 1.5 1.4
  Vomiting 1.0 -
  Stomatitis 1.0 -
  Increased Blood in Stool - 3.4
Metabolism and Nutrition Disorders
  Anorexia 1.3 1.9
Nervous System Disorders
  Headache 5.0 4.8
  Insomnia - 2.4
General Disorders and Administration Site Conditions
  Fatigue/Drowsiness/Lethargy 1.8 2.9
Psychiatric Disorders
  Depression 1.5 -
Ear and Labyrinth Disorders
  Vertigo/Dizziness 1.0 -
Skin and Subcutaneous Tissue Disorders
  Rash 2.3 1.4
  Itching 1.3 -
Musculoskeletal and Connective Tissue Disorders
  Arthralgia/Joint Pain 4.0 2.9
Infections and Infestations
  Upper Respiratory Infection 1.5 -

Over 2,500 patients have been treated with olsalazine in various controlled and uncontrolled clinical studies. In these as well as in post-marketing experience, olsalazine was administered mainly to patients intolerant to sulfasalazine. There have been rare reports of the following adverse effects in patients receiving olsalazine. These were often difficult to distinguish from possible symptoms of the underlying disease or from the effects of prior and/or concomitant therapy. A causal relationship to the drug has not been demonstrated for some of these reactions.

Blood and Lymphatic System Disorders

Anemia, Eosinophilia, Hemolytic anemia, Interstitial pulmonary disease, Leukopenia, Lymphopenia, Neutropenia, Reticulocytosis, Thrombocytopenia

Cardiac Disorders

Chest pains, Heart block second degree, Myocarditis, Palpitations, Pericarditis, Peripheral edema, Shortness of breath, Tachycardia

A patient who developed thyroid disease 9 days after starting DIPENTUM (olsalazine sodium capsules) was given propranolol and radioactive iodine and subsequently developed shortness of breath and nausea. The patient died 5 days later with signs and symptoms of acute diffuse myocarditis.

Ear and Labyrinth Disorders


Eye Disorders

Dry eyes, Vision blurred, Watery eyes

Gastrointestinal Disorders

Abdominal pain (upper), Diarrhea with dehydration, Dry mouth, Epigastric discomfort, Flare in symptoms, Flatulence, Increased blood in stool, Pancreatitis, Rectal bleeding, Rectal discomfort

In a double-blind, placebo-controlled study, increased frequency and severity of diarrhea were reported in patients randomized to olsalazine 500 mg B.I.D. with concomitant pelvic radiation.

Rare cases of granulomatous hepatitis and nonspecific, reactive hepatitis have been reported in patients receiving olsalazine. Additionally, a patient developed mild cholestatic hepatitis during treatment with sulfasalazine and experienced the same symptoms two weeks later after the treatment was changed to olsalazine. Withdrawal of olsalazine led to complete recovery in these cases.

General Disorders and Administration Site Conditions

Fever chills, Hot flashes, Irritability, Rigors

Immune System Disorders

Bronchospasm, Erythema nodosum


ALT (SGPT) or AST (SGOT) elevated beyond the normal range.

Musculoskeletal and Connective Tissue Disorders

Muscle cramps

Nervous System Disorders

Insomnia, Paraesthesia, Tremors

Psychiatric Disorders

Mood swings

Renal and Urinary Disorders

Dysuria, Hematuria, Interstitial nephritis, Nephrotic syndrome, Proteinuria, Urinary frequency

Reproductive System and Breast Disorders

Impotence, Menorrhagia

Skin and Subcutaneous Tissue Disorders

Alopecia, Erythema, Photosensitivity reaction

Vascular Disorders

Hypertension, Orthostatic hypotension


The following events have been identified during post-approval use of products that contain (or are metabolized to) mesalamine in clinical practice. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These events have been chosen for inclusion due to a combination of seriousness, frequency of reporting, or potential causal connection to mesalamine:

Blood and Lymphatic System Disorders

Aplastic anemia, Pancytopenia

General Disorders and Administration Site Conditions


Hepatobiliary Disorders

Hepatic enzyme increased, Hepatitis, Increased bilirubin

Reports of hepatotoxicity, including elevated liver function tests (SGOT/AST, SGPT/ALT, GGT, LDH, alkaline phosphatase, bilirubin), jaundice, cholestatic jaundice, cirrhosis, and possible hepatocellular damage including liver necrosis and liver failure. Some of these cases were fatal. One case of Kawasaki-like syndrome, which included hepatic function changes, was also reported.

Musculoskeletal and Connective Tissue Disorders


Respiratory, Thoracic and Mediastinal Disorders

Dyspnoea, Interstitial lung disease

Skin and Subcutaneous Tissue Disorders

Angioneurotic oedema

Nervous System Disorders

Paraesthesia, Peripheral neuropathy

Renal and Urinary Disorders

Interstitial nephritis

Drug Abuse And Dependency


None reported.


Drug dependence has not been reported with chronic administration of olsalazine.