olsalazine (Rx)

Brand and Other Names:Dipentum

Dosing & Uses


Dosage Forms & Strengths


  • 250mg

Ulcerative Colitis

Maintenance: 1g PO qDay in 2 divided doses


Take with food

Other Indications & Uses

Maintenance of remission of ulcerative colitis in patients who are intolerant of sulfasalazine

Dosing Modifications

Renal impairment

  • Discontinue therapy if renalfunction deteriorates while on therapy

Safety & efficacy not established


Adverse Effects


Diarrhea (17%)

Abdominal pain (11%)


Nausea/vomiting (6%)

Headache (5%)

Arthralgia (4%)

Dyspepsia (4%)

Joint pain (4%)

Rash/itching (3.6%)

Fatigue (1.8%)

Bloating (1.5%)

Depression (1.5%)

Upper respiratory infection (1.5%)

Anorexia (1.3%)

Dizziness (1%)

Postmarketing Reports

Respiratory, thoracic and mediastinal disorders: Dyspnea, Interstitial lung disease, pleurisy/pleuritis

Skin and subcutaneous tissue disorders: Angioneurotic edema, SJS/TEN, DRESS, and AGEP

Renal and urinary disorders: Nephritis, nephrolithiasis, urine discoloration




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


Mesalamine-induced acute intolerance syndrome may occur; drug is converted to mesalamine, which has been associated with acute intolerance syndrome that may be difficult to distinguish from 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 similar reaction to 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 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 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, kidney was 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 kidney, and risk of adverse reactions may be greater in patients with impaired renal function
  • Evaluate renal function in all patients prior to initiation and periodically while on therapy

Pregnancy & Lactation

Pregnancy Category: C


Not known whether drug distributed into breast milk, use caution

5-ASA is excreted in breast milk & may cause diarrhea in infant

However little is absorbed from oral olsalazine


Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.



Mechanism of Action

Converted to 5-aminosalicylic acid (mesalamine) by gastrointestinal flora which is thought to be the therapeutically active component; works topically rather tha systemically


~2.4% of a single 1 g dose

Peak plasma (single 1 g dose)

  • Olsalazine: 1.6-6.2 umol/L
  • 5-aminosalicylic acid (5-ASA): 0-4.3umol/L
  • N-acetyl-5-ASA: 1.7-8.7 umol/L


Protein bound: 99%


>90% converted to 5-ASA in the gut

5-ASA is deactivated to N-Ac-5-ASA in colonic epithelium & liver

Approx. 0.1% converted to olsalazine-O-sulfate (Olsalazine-S) in liver



  • Olsalazine: 0.9 hr
  • 5-ASA: 45 min
  • N-Ac-5-ASA: 80 min
  • Olsalazine-S (~0.1%): 7 d


  • Urine: 20% (mostly N-Ac-5-ASA)
  • Feces: 80% (both 5-ASA & N-Ac-5-ASA)


Dipentum oral
250 mg capsule

Copyright © 2010 First DataBank, Inc.


Patient Handout

Patient Education
olsalazine oral




USES: Olsalazine is used to treat a certain type of bowel disease called ulcerative colitis. It does not cure ulcerative colitis, but it may decrease symptoms such as stomach pain, diarrhea, and rectal bleeding caused by irritation/swelling of the colon/rectum. After an attack is treated, olsalazine is used to increase the amount of time between attacks.Olsalazine is an aminosalicylate anti-inflammatory drug. It is believed to work by blocking the production of certain natural substances (such as prostaglandins) that may cause pain and swelling.

HOW TO USE: Take this medication by mouth as directed by your doctor, usually twice a day about 12 hours apart. Take with food or after meals to prevent stomach upset. Dosage is based on your medical condition and response to treatment.Drink plenty of fluids during treatment with this medication unless otherwise directed by your doctor. This will help prevent kidney stones.Use this medication regularly in order to get the most benefit from it. To help you remember, take it at the same times each day.Tell your doctor if your condition does not get better or if it gets worse.

SIDE EFFECTS: Headache, nausea, vomiting, or loss of appetite may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if diarrhea occurs. Your doctor may need to lower your dose or prescribe another medication to treat the diarrhea.Tell your doctor right away if you have any serious side effects, including: nausea/vomiting that doesn't stop, severe stomach/abdominal pain, pale stools, unusual tiredness, signs of kidney problems (such as change in the amount of urine, blood in the urine), dark urine, yellowing eyes/skin, easy bruising/bleeding.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: fever, swollen lymph nodes, rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking olsalazine, tell your doctor or pharmacist if you are allergic to it; or to aspirin or related drugs (salicylates such as mesalamine, NSAIDs such as ibuprofen, balsalazide, sulfasalazine); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: asthma, growths in the nose (nasal polyps), kidney problems, liver problems, radiation treatment in the pelvic area.This medicine may cause stomach bleeding. Daily use of alcohol may increase your risk for stomach bleeding, especially when combined with this medicine. Check with your doctor or pharmacist for more information.This medication is similar to aspirin. Children and teenagers younger than 18 years should not take aspirin or aspirin-related medications (such as salicylates) if they have chickenpox, flu, or any undiagnosed illness, or if they have just been given a live virus vaccine (such as varicella vaccine), without first consulting a doctor about Reye's syndrome, a rare but serious illness.This medication may make you more sensitive to the sun. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you get sunburned or have skin blisters/redness.Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).During pregnancy, this drug should be used only when clearly needed. Discuss the risks and benefits with your doctor.This drug may pass into breast milk and could have undesirable effects on a nursing infant. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug include: mercaptopurine, thioguanine.Olsalazine is very similar to mesalamine. Do not use mesalamine medications taken by mouth while using olsalazine.This medication may interfere with certain lab tests (such as urine normetanephrine levels), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.

OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

NOTES: Do not share this medication with others.Lab and/or medical tests (such as kidney/liver function) may be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

STORAGE: Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

Information last revised July 2023. Copyright(c) 2023 First Databank, Inc.

IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.



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The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

Tier Description
1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
NC NOT COVERED – Drugs that are not covered by the plan.
Code Definition
PA Prior Authorization
Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
QL Quantity Limits
Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
ST Step Therapy
Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
OR Other Restrictions
Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.