Side Effects of Dipentum (olsalazine)

Does Dipentum (olsalazine) cause side effects?

Dipentum (olsalazine) is a derivative of salicylic acid used to treat inflammatory diseases of the colon such as ulcerative colitis (UC). Inactive itself, Dipentum is converted by the bacteria in the colon to its active form, mesalamine.

Following oral administration very little of the Dipentum (less than 10%) is absorbed from the intestine into the body. The benefit of mesalamine is believed to be due to a local effect from within the colon.

Mesalamine also is thought to be the active component of another drug used for treating inflammatory diseases of the intestines, sulfasalazine (Azulfidine).

Common side effects of Dipentum include

Serious side effects of Dipentum include

Drug interactions of Dipentum include

There are no adequate and well-controlled studies of Dipentum in pregnant women. Dipentum should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Mesalamine, which is the active form of Dipentum, may be secreted into breast milk and cause diarrhea in the infant. Consult your doctor before breastfeeding

What are the important side effects of Dipentum (olsalazine)?

Common side effects are:

Other important side effects include:

Gastrointestinal disturbances commonly occur in persons who take olsalazine. Diarrhea occurs in about 1 of every 6 persons who take it; about one in 20 need to discontinue therapy because the diarrhea is severe.

Abdominal pain or cramps occur in 1 in 10 persons, and nausea or vomiting occurs in 1 in 20. Other side effects, including dizziness, depression, and headache, occur less frequently than gastrointestinal effects during therapy. Rashes occur in 2.3% of persons and joint pain in 4%.

Dipentum (olsalazine) side effects list for healthcare professionals

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.

What drugs interact with Dipentum (olsalazine)?

The co-administration of salicylates and low molecular weight heparins or heparinoids may result in an increased risk of bleeding (i.e., hematomas) following neuraxial anesthesia.

Salicylates should be discontinued prior to the initiation of a low molecular weight heparin or heparinoid. If this is not possible, it is recommended to monitor patients closely for bleeding.

Increased prothrombin time in patients taking concomitant warfarin has been reported.

The co-administration of olsalazine and 6-mercaptopurine or thioguanine may result in an increased risk of myelosuppression. If co-administered with 6-mercaptopurine, it is recommended to use the lowest possible doses of each drug and to monitor the patient, especially for leukopenia. In case of co-administration with thioguanine, careful monitoring of blood counts is recommended.

It is recommended not to give salicylates for six weeks after the varicella vaccine to avoid a possible increased risk of developing Reye's syndrome.

Drug/Laboratory Test Interactions

None known.


Dipentum (olsalazine) is a derivative of salicylic acid used to treat inflammatory diseases of the colon such as ulcerative colitis (UC). Common side effects of Dipentum include gastrointestinal disturbances (diarrhea, abdominal pain or cramps, and nausea), dizziness, depression, headache, rashes, and joint pain. There are no adequate and well-controlled studies of Dipentum in pregnant women. Mesalamine, which is the active form of Dipentum, may be secreted into breast milk and cause diarrhea in the infant.

Treatment & Diagnosis

Medications & Supplements

FDA Logo

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

FDA Prescribing Information

Professional side effects and drug interactions sections courtesy of the U.S. Food and Drug Administration.