Reviewed on 1/12/2023

What Is Olsalazine and How Does It Work?

Olsalazine is a prescription medication used for the treatment of ulcerative colitis.

  • Olsalazine is available under the following different brand names: Dipentum

What Are Side Effects Associated with Using Olsalazine?

Common side effects of Olsalazine include:

  • diarrhea,
  • stomach pain,
  • upset stomach,
  • rash,
  • itching,
  • headache, and
  • joint pain

Serious side effects of Olsalazine include:

  • hives,
  • difficulty breathing,
  • swelling of the face, lips, tongue, or throat,
  • severe or ongoing diarrhea,
  • fever,
  • stomach pain,
  • cramping,
  • bloody diarrhea,
  • chest pain,
  • shortness of breath,
  • fast or pounding heartbeats,
  • fever,
  • chills,
  • tiredness,
  • mouth sores,
  • skin sores,
  • easy bruising,
  • unusual bleeding,
  • pale skin,
  • cold hands and feet,
  • lightheadedness,
  • loss of appetite,
  • stomach pain (upper right side),
  • dark urine,
  • clay-colored stools,
  • yellowing of the skin or eyes,
  • sudden and severe pain in the lower back or side,
  • blood in your urine, and
  • pain or burning while urinating

Rare side effects of Olsalazine include:

  • none 

Seek medical care or call 911 at once if you have the following serious side effects:

  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheadedness, or passing out.

This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Are the Dosages of Olsalazine?

Adult dosage


  • 250 mg

Ulcerative Colitis

Adult dosage

  • Maintenance: 1g orally every day in 2 divided doses

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”

What Other Drugs Interact with Olsalazine?

If your medical doctor is using this medicine to treat your pain, 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.

  • Olsalazine has no noted severe interactions with any other drugs.
  • Olsalazine has no noted serious interactions with any other drugs.
  • Olsalazine has no noted moderate interactions with any other drugs.
  • Olsalazine has no noted minor interactions with any other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your healthcare professional or doctor for additional medical advice, or if you have health questions or concerns.

What Are Warnings and Precautions for Olsalazine?


  • Patients with known or suspected hypersensitivity to salicylates, aminosalicylates or their metabolites, or excipients

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Olsalazine?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Olsalazine?”


  • Mesalamine-induced acute intolerance syndrome may occur; the drug is converted to mesalamine, which has been associated with acute intolerance syndrome that may be difficult to distinguish from an exacerbation of ulcerative colitis; symptoms include cramping, acute abdominal pain and bloody diarrhea, sometimes fever, headache, and rash; monitor patients for worsening of symptoms while on treatment; discontinue therapy if acute intolerance syndrome suspected
  • Some patients who have experienced a hypersensitivity reaction to sulfasalazine have a similar reaction to the drug or to other compounds that contain or are converted to mesalamine; mesalamine-induced hypersensitivity reactions may present as internal organ involvement, including myocarditis, pericarditis, nephritis, hepatitis, pneumonitis, and hematologic abnormalities; evaluate patients immediately if signs or symptoms of a hypersensitivity reaction present; discontinue therapy if an alternative etiology for signs and symptoms cannot be established
  • There have been reports of hepatic failure in patients with pre-existing liver disease receiving therapy; because the drug is converted to mesalamine, evaluate risks and benefits of therapy in patients with known liver impairment
  • Patients with pre-existing skin conditions such as atopic dermatitis and atopic eczema have reported more severe photosensitivity reactions when receiving therapy; advise patients to avoid sun exposure, wear protective clothing, and use a broad-spectrum sunscreen when outdoors
  • Cases of nephrolithiasis have been reported with the use of mesalamine; active moiety in drug, including stones with 100% mesalamine content; mesalamine-containing stones are radiotransparent and undetectable by standard radiography or computed tomography (CT); ensure adequate hydration during treatment
  • Severe cutaneous adverse reactions, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP) reported with use, discontinue therapy at first signs or symptoms of severe cutaneous adverse reactions or other signs of hypersensitivity and consider further evaluation
  • Renal toxicity
    • Renal impairment, including minimal change disease, acute and chronic interstitial nephritis, and renal failure reported in patients given products that contain mesalamine or are converted to mesalamine; in animal studies, the kidney was a principal organ of mesalamine toxicity
    • Evaluate the risks and benefits of therapy in patients with known renal impairment or a history of renal disease or taking concomitant nephrotoxic drugs
    • Mesalamine is known to be substantially excreted by the kidney, and the risk of adverse reactions may be greater in patients with impaired renal function
    • Evaluate renal function in all patients before initiation and periodically while on therapy

Pregnancy and Lactation

  • Use with caution if benefits outweigh risks during pregnancy
  • Lactation
    • Not known whether the drug is distributed into breast milk, use caution
    • 5-ASA is excreted in breast milk & may cause diarrhea in the infant
    • However little is absorbed from oral olsalazine
    • Avoid

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