Dipentum (Olsalazine Sodium)
Aminosalicylate for the treatment and maintenance of ulcerative colitis
Quick Facts About Dipentum
Key Takeaways About Dipentum
- Targeted colon delivery: Dipentum is a prodrug that releases anti-inflammatory 5-ASA directly in the colon, minimizing systemic absorption and side effects
- Sulfonamide-free alternative: Unlike sulfasalazine, Dipentum does not contain a sulfonamide component, making it suitable for patients with sulfonamide intolerance
- Take with food: Always take Dipentum capsules immediately after meals to reduce the risk of gastrointestinal side effects, particularly diarrhea
- Regular monitoring needed: Your doctor may order periodic blood tests and kidney function assessments during long-term treatment
- Report unusual symptoms: Seek immediate medical attention if you develop facial swelling, difficulty breathing, unexplained fever, sore throat, or unusual bruising or bleeding
What Is Dipentum and What Is It Used For?
Dipentum (olsalazine sodium) is an oral aminosalicylate medication used to treat and maintain remission of ulcerative colitis, a chronic inflammatory disease of the large intestine that causes diarrhea, abdominal pain, and rectal bleeding. It works by delivering anti-inflammatory 5-aminosalicylic acid directly to the colon.
Ulcerative colitis is a form of inflammatory bowel disease (IBD) that causes long-lasting inflammation and ulcers in the innermost lining of the large intestine (colon) and rectum. According to the World Health Organization, IBD affects millions of people worldwide, with ulcerative colitis being one of the two main forms alongside Crohn's disease. The condition follows a relapsing-remitting course, meaning patients experience periods of active disease (flares) alternating with periods of remission.
Dipentum contains the active substance olsalazine sodium, which is classified as an aminosalicylate or 5-ASA derivative. Each hard capsule contains 250 mg of olsalazine sodium. The capsules are beige in color, filled with yellow powder, and marked "DIPENTUM 250 mg" on the shell. Olsalazine is a prodrug, meaning it is not pharmacologically active in its original form but is converted to the active drug within the body.
How Dipentum Works
The mechanism of action of Dipentum is elegantly targeted. Olsalazine consists of two molecules of 5-aminosalicylic acid (5-ASA, also known as mesalazine) joined together by an azo bond. When taken orally, the olsalazine molecule passes through the stomach and small intestine largely intact, as the azo bond is resistant to digestion in the upper gastrointestinal tract. Only when it reaches the colon do bacteria naturally present in the large intestine (specifically bacterial azoreductases) cleave the azo bond, releasing two molecules of 5-ASA exactly where they are needed.
Once released in the colon, 5-ASA exerts its anti-inflammatory effect directly on the intestinal mucosa through several mechanisms. It inhibits the production of prostaglandins and leukotrienes, which are key mediators of inflammation. It also acts as a scavenger of reactive oxygen species (free radicals) that contribute to tissue damage in the inflamed colon. Additionally, 5-ASA modulates the activity of certain immune cells in the intestinal wall, reducing the inflammatory cascade that drives ulcerative colitis.
This targeted delivery system is one of the key advantages of Dipentum. Because approximately 98–99% of the olsalazine reaches the colon intact, the systemic absorption of 5-ASA is minimal. This means the anti-inflammatory action is concentrated where it is most needed — the diseased colonic mucosa — while minimizing exposure to the rest of the body and thereby reducing the risk of systemic side effects.
Clinical studies, including those reviewed by the European Medicines Agency (EMA) and endorsed by international gastroenterology guidelines from the European Crohn's and Colitis Organisation (ECCO) and the American College of Gastroenterology (ACG), have demonstrated that aminosalicylates like olsalazine are effective for both inducing and maintaining remission in mild to moderate ulcerative colitis. Dipentum is particularly valuable as an alternative for patients who are intolerant to sulfasalazine, the oldest aminosalicylate, which contains a sulfonamide component responsible for many side effects.
Dipentum is designed for long-term maintenance therapy of ulcerative colitis. Even when you feel well and symptoms have resolved, it is important to continue taking the medication as prescribed by your doctor to prevent disease relapse. Stopping treatment prematurely significantly increases the risk of flare-ups.
What Should You Know Before Taking Dipentum?
Before starting Dipentum, tell your doctor about any allergies to salicylates (such as aspirin), kidney or liver problems, severe allergies, or asthma. Dipentum must not be used by anyone hypersensitive to olsalazine, other salicylates, or any of its excipients. Pregnancy and breastfeeding require special medical advice.
Dipentum is a well-established medication for ulcerative colitis, but like all prescription medicines, it requires careful consideration of your individual health profile before starting treatment. Your doctor will evaluate your medical history and current health status to determine if Dipentum is appropriate for you. Being fully informed about the precautions and contraindications helps ensure safe and effective treatment.
Contraindications
You must not take Dipentum if:
- You are allergic (hypersensitive) to olsalazine sodium or any of the other ingredients in the capsules
- You are allergic to other salicylates, which are a group of related active substances found in certain pain and fever medications (such as aspirin)
- You have a known hypersensitivity to any of the excipients, including magnesium stearate, gelatin, caramel color (E 150), or titanium dioxide (E 171)
If you suspect you may be allergic to any of these substances, discuss your concerns with your doctor or pharmacist before starting treatment. Cross-reactivity between different salicylate compounds is possible but not universal, so your doctor will make an individualized assessment.
Warnings and Precautions
Talk to your doctor before taking Dipentum if any of the following conditions apply to you:
- Impaired kidney function: Olsalazine is partly eliminated through the kidneys, and impaired renal function may increase the risk of adverse effects. Your doctor may need to monitor your kidney function more closely during treatment
- Impaired liver function: Liver disease may affect the metabolism and clearance of the medication. Liver function tests may be performed before and during treatment
- Severe allergy or asthma: Patients with pre-existing severe allergic conditions or asthma may be at increased risk of hypersensitivity reactions to salicylate-containing medications
- Blood disorders: If you have a history of blood cell abnormalities, your doctor should be informed, as aminosalicylates can rarely affect blood cell production
Stop taking Dipentum and contact your doctor immediately if you develop any of the following symptoms:
- Angioedema: swelling of the face, tongue, or throat
- Difficulty swallowing or breathing
- Hives (urticaria) with breathing difficulties
- Signs of hematotoxicity: unexplained fever, sore throat, mouth sores, unusual bruising, or bleeding
These may indicate serious allergic reactions or blood cell abnormalities that require urgent medical evaluation.
Pregnancy and Breastfeeding
There is limited clinical experience with the use of Dipentum during pregnancy. If you are pregnant, think you may be pregnant, or are planning to become pregnant, you should not take Dipentum without first consulting your doctor. Your healthcare provider will carefully weigh the potential benefits of continued treatment against any possible risks to the developing baby.
Olsalazine and its active metabolite 5-ASA may pass into breast milk. If you are breastfeeding or planning to breastfeed, consult your doctor before taking Dipentum. Your doctor will consider whether the benefits of treatment outweigh the potential risks to the nursing infant. In some cases, your doctor may recommend monitoring the infant for signs of diarrhea if you continue both breastfeeding and Dipentum therapy.
Driving and Operating Machinery
Dipentum has no known effect on the ability to drive or operate machinery. However, as with any medication, individual responses can vary. You are responsible for assessing whether you are fit to drive or perform tasks requiring alertness. If you experience side effects such as dizziness or headache, exercise caution until you know how the medication affects you. Consult your doctor or pharmacist if you are uncertain.
Children and Adolescents
The use of Dipentum in children should be under the guidance and supervision of a pediatric gastroenterologist. Dosing in pediatric patients is typically adjusted based on body weight, and children may require closer monitoring for side effects. Discuss the specific risks and benefits with your child's doctor before initiating treatment.
How Does Dipentum Interact with Other Drugs?
Dipentum can interact with certain cancer medications (mercaptopurine, thioguanine) by inhibiting the enzyme that breaks them down, potentially increasing toxicity. It may also enhance the anticoagulant effect of blood-thinning medications such as heparin and warfarin. Vaccination timing may need adjustment during treatment.
Like many medications, Dipentum has the potential to interact with other drugs, either by affecting their metabolism or by having additive or opposing effects. It is essential to tell your doctor or pharmacist about all medications you are currently taking, have recently taken, or plan to take, including over-the-counter medicines, herbal supplements, and vitamins. Understanding these interactions helps your healthcare team optimize your treatment and minimize the risk of adverse effects.
Major Interactions
| Interacting Drug | Effect | Recommendation |
|---|---|---|
| Mercaptopurine | Olsalazine inhibits thiopurine methyltransferase (TPMT), potentially increasing mercaptopurine levels and risk of bone marrow suppression | Dose adjustment and close blood count monitoring required; inform your oncologist |
| Thioguanine (6-TG) | Same TPMT inhibition mechanism as with mercaptopurine, leading to increased thioguanine toxicity | Dose adjustment and close blood count monitoring required; discuss with your doctor |
| Heparin | Aminosalicylates may potentiate the anticoagulant effect of heparin, increasing bleeding risk | Monitor coagulation parameters more frequently; watch for signs of unusual bleeding |
| Warfarin | Aminosalicylates may enhance the anticoagulant effect of warfarin, increasing INR and bleeding risk | More frequent INR monitoring; dose adjustment of warfarin may be necessary |
Vaccination Considerations
If you are planning to receive a vaccination, particularly the varicella (chickenpox) vaccine, you should consult your doctor about whether to temporarily discontinue Dipentum around the time of vaccination and for a limited period afterward. This precaution is based on the theoretical concern that aminosalicylates may affect the immune response to live vaccines. Your doctor will advise you on the appropriate timing based on your individual clinical situation.
Minor Interactions and General Precautions
While major interactions are well-documented, aminosalicylates may also interact with other medications in more subtle ways. The following general precautions should be kept in mind:
- Azathioprine: Like mercaptopurine, azathioprine is a thiopurine immunosuppressant sometimes used in IBD. The same TPMT inhibition concern applies, and concurrent use requires careful monitoring
- NSAIDs (non-steroidal anti-inflammatory drugs): Concurrent use of NSAIDs with aminosalicylates may increase the risk of kidney toxicity. Use with caution and under medical supervision
- Digoxin: Aminosalicylates may reduce the absorption of digoxin. If you take digoxin, your doctor may need to monitor your levels more closely
- Folic acid supplements: Aminosalicylates may impair folate absorption. Your doctor may recommend folic acid supplementation, particularly during pregnancy planning
Always carry an up-to-date list of all your medications, including prescription drugs, over-the-counter medicines, and supplements. Share this list with every healthcare provider you visit, including dentists and pharmacists, to help identify potential drug interactions.
What Is the Correct Dosage of Dipentum?
The usual adult dose of Dipentum is 2 capsules (500 mg) twice daily, taken immediately after meals. Your doctor may start with a lower dose and gradually increase it. The capsules should be swallowed whole. In case of overdose, seek immediate medical attention.
Your doctor will determine the appropriate dose of Dipentum based on your specific condition, disease severity, and individual response to treatment. It is important to follow your doctor's instructions exactly and not to adjust the dose on your own. The dosage recommendations below serve as a general guide; your prescribed dose may differ.
Adults
Standard Adult Dosage
The usual recommended dose for adults is 2 capsules (500 mg) twice daily, for a total daily dose of 1,000 mg (1 gram). Dipentum should be taken at regular intervals, immediately after meals. Taking the capsules with food helps reduce the most common side effect, diarrhea, and improves gastrointestinal tolerance.
Starting Dose
In the initial phase of treatment, your doctor may prescribe a lower starting dose to allow your body to adjust to the medication. This gradual introduction can help minimize side effects, particularly diarrhea. The dose is then increased to the target maintenance dose over a period of days to weeks as tolerated.
Maintenance Therapy
Once remission is achieved, Dipentum is typically continued as long-term maintenance therapy. The maintenance dose is usually the same as the treatment dose: 500 mg twice daily. Continuous maintenance therapy significantly reduces the risk of disease relapse compared to stopping treatment. Your doctor will regularly review whether continued therapy is appropriate.
Children
Dosing in pediatric patients is determined by the treating physician, typically based on body weight. Children should be treated under the supervision of a pediatric gastroenterologist experienced in managing inflammatory bowel disease. The safety and efficacy profile in children is generally consistent with that observed in adults, but individual monitoring is important.
Elderly
No specific dose adjustment is routinely required for elderly patients. However, elderly patients may have age-related changes in kidney or liver function that could affect drug clearance. Your doctor may monitor your renal and hepatic function more closely and adjust the dose if necessary.
Administration Instructions
- Swallow capsules whole — do not open, crush, or chew the capsules
- Take immediately after meals — food helps reduce gastrointestinal side effects
- Take at regular intervals — maintain consistent timing (e.g., after breakfast and after dinner)
- Do not double the dose — if you miss a dose, take it as soon as you remember unless it is almost time for the next dose. In that case, skip the missed dose and continue your regular schedule
Missed Dose
If you forget to take a dose of Dipentum, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and take the next one at the usual time. Do not take a double dose to make up for a forgotten dose. If you frequently forget doses, consider setting a reminder or associating the medication with specific mealtimes to help maintain adherence.
Overdose
If you take more Dipentum than prescribed, or if a child accidentally ingests the medication, contact your doctor, hospital emergency department, or poison control center immediately for an assessment of the risk and guidance. Symptoms of overdose may include nausea, vomiting, diarrhea, and abdominal discomfort. Treatment of overdose is generally supportive, focusing on managing symptoms and preventing complications.
What Are the Side Effects of Dipentum?
The most common side effect of Dipentum is diarrhea, which is usually temporary. Other common side effects include headache, nausea, skin rash, and joint pain. Uncommon but more serious side effects include blood cell abnormalities, heart inflammation, and liver problems. Report any unusual or persistent symptoms to your doctor.
Like all medicines, Dipentum can cause side effects, although not everybody gets them. Most side effects are mild and tend to improve as your body adjusts to the medication. However, some side effects can be more serious and require prompt medical attention. Understanding the possible side effects and knowing when to seek help is an important part of managing your treatment safely.
The most frequently reported side effect is diarrhea, which is usually transient in nature and often improves with continued treatment. If diarrhea is persistent, severe, or accompanied by blood, you should contact your doctor, as this may need to be distinguished from a flare of your underlying ulcerative colitis.
Common (affects up to 1 in 10 patients)
- Headache: mild to moderate headache, usually resolves with continued use
- Diarrhea: the most frequently reported side effect, typically transient
- Nausea: feeling sick, particularly when taken on an empty stomach
- Skin rash: various types of skin eruptions
- Joint pain (arthralgia): pain in one or more joints
Uncommon (affects up to 1 in 100 patients)
- Thrombocytopenia: decreased platelet count, which may cause easy bruising or bleeding
- Depression: changes in mood or emotional state
- Dizziness: sensation of lightheadedness or unsteadiness
- Paresthesia: tingling or "pins and needles" sensations
- Tachycardia: rapid heartbeat
- Dyspnea: shortness of breath
- Vomiting
- Dyspepsia: indigestion or stomach discomfort
- Elevated liver enzymes: detected on blood tests
- Pruritus: itching of the skin
- Alopecia: hair loss or thinning
- Photosensitivity: increased sensitivity of the skin to sunlight
- Urticaria: hives
- Myalgia: muscle pain
- Fever
Not Known (frequency cannot be estimated from available data)
- Anemia: low red blood cell count causing fatigue and weakness
- Eosinophilia: increased numbers of a type of white blood cell
- Neutropenia and leukopenia: low white blood cell counts increasing infection susceptibility
- Pancytopenia: decrease in all types of blood cells
- Pericarditis: inflammation of the membrane around the heart
- Myocarditis: inflammation of the heart muscle
- Palpitations: awareness of heartbeat
- Upper abdominal pain
- Pancreatitis: inflammation of the pancreas, causing severe abdominal pain
- Hepatitis: inflammation of the liver
- Elevated bilirubin: yellowing of skin or eyes may occur
- Angioedema: allergic swelling of the skin and mucous membranes (face, tongue, throat)
- Interstitial nephritis: inflammation of the kidneys
- Interstitial lung disease: inflammation of the lung tissue
- Peripheral neuropathy: damage to nerves in the hands and feet, causing tingling, numbness, or pain
- Blurred vision
Managing Side Effects
The most common side effect, diarrhea, can often be managed by taking Dipentum immediately after meals and, if necessary, by starting with a lower dose that is gradually increased. If diarrhea is persistent, severe, or accompanied by blood or mucus, contact your doctor, as this may indicate a disease flare rather than a medication side effect.
Photosensitivity reactions can be minimized by avoiding prolonged sun exposure, wearing protective clothing, and using high-factor sunscreen during treatment. If you notice any skin changes after sun exposure, inform your doctor.
When to Seek Urgent Medical Help
Contact your doctor immediately or go to the nearest emergency department if you experience:
- Swelling of the face, lips, tongue, or throat (angioedema)
- Difficulty breathing or swallowing
- Severe chest pain or persistent palpitations (possible pericarditis or myocarditis)
- Severe abdominal pain (possible pancreatitis)
- Unexplained fever, sore throat, or mouth ulcers (possible blood cell abnormalities)
- Unusual bruising or bleeding (possible thrombocytopenia or pancytopenia)
- Yellowing of the skin or eyes (possible hepatitis)
- Progressive numbness or weakness in the extremities (possible peripheral neuropathy)
If you experience any side effects, whether listed above or not, talk to your doctor or pharmacist. You can also report side effects directly to your national pharmacovigilance authority. By reporting side effects, you help provide more information on the safety of this medicine.
How Should You Store Dipentum?
Store Dipentum at or below 25°C (77°F), in its original packaging, and keep out of the reach and sight of children. Do not use after the expiration date printed on the packaging. Do not dispose of medications via household waste or wastewater.
Proper storage of medication is important to ensure it remains effective and safe throughout its shelf life. Dipentum capsules should be stored under the following conditions:
- Temperature: Store at or below 25°C (77°F). Avoid exposure to excessive heat, direct sunlight, or freezing temperatures
- Moisture: Keep the capsules in their original packaging to protect from moisture. Do not store in the bathroom or other humid environments
- Child safety: Keep out of the sight and reach of children. Consider using a child-resistant storage location
- Expiration: Do not use Dipentum after the expiration date stated on the label. The expiration date refers to the last day of the indicated month
When disposing of unused or expired medication, do not throw it in the household trash or flush it down the toilet. Ask your pharmacist about proper medication disposal methods in your area. Many pharmacies and healthcare facilities offer medication take-back programs. Proper disposal helps protect the environment.
What Does Dipentum Contain?
Each Dipentum capsule contains 250 mg of olsalazine sodium as the active ingredient. The capsule also contains magnesium stearate as an excipient, with a gelatin capsule shell colored with caramel (E 150) and titanium dioxide (E 171). The capsule is printed with shellac, iron oxide (E 172), and propylene glycol.
Active Ingredient
The active substance in Dipentum is olsalazine sodium, present at a dose of 250 mg per capsule. Olsalazine sodium is the disodium salt of 3,3′-azobis(6-hydroxybenzoic acid), a molecule formed by linking two molecules of 5-aminosalicylic acid through an azo bond. This unique chemical structure allows targeted delivery of the anti-inflammatory 5-ASA to the colon.
Excipients (Inactive Ingredients)
The following excipients are used in the formulation of Dipentum capsules:
- Magnesium stearate — a lubricant used in the capsule filling to ensure uniform powder flow during manufacturing
Capsule Shell Components
- Gelatin — forms the hard capsule shell
- Caramel color (E 150) — provides the beige coloring of the capsule
- Titanium dioxide (E 171) — an opacifying agent used in the capsule shell
Capsule Printing Ink
- Shellac — a natural resin used as a base for the ink
- Iron oxide (E 172) — provides the color for the printed text
- Propylene glycol — a solvent used in the printing ink
Appearance
Dipentum capsules are beige-colored hard gelatin capsules filled with yellow powder. Each capsule is marked "DIPENTUM® 250 mg" on the shell. Inspect the capsules before use; do not take any capsule that appears damaged, discolored, or has an unusual odor.
Frequently Asked Questions About Dipentum
Dipentum (olsalazine sodium) is used to treat and maintain remission of ulcerative colitis, a chronic inflammatory bowel disease that affects the large intestine. It works by delivering the anti-inflammatory compound 5-aminosalicylic acid (5-ASA) directly to the colon, where it reduces inflammation of the intestinal lining. Dipentum is particularly useful for patients who cannot tolerate sulfasalazine due to its sulfonamide component.
The most common side effect of Dipentum is diarrhea, which usually improves over time as your body adjusts to the medication. Other common side effects include headache, nausea, skin rash, and joint pain. Taking the capsules immediately after meals and starting with a lower dose can help minimize these effects. If diarrhea is persistent or severe, consult your doctor as a dose adjustment may be needed.
Take Dipentum capsules immediately after meals, at regular intervals throughout the day. The capsules should be swallowed whole — do not open, crush, or chew them. The usual adult dose is 2 capsules (500 mg) twice daily. Your doctor may start with a lower dose and increase it gradually. Always follow your doctor's specific dosage instructions, and continue taking the medication even when you feel well to prevent disease relapse.
There is limited clinical experience with Dipentum use during pregnancy. Do not take Dipentum without first consulting your doctor if you are pregnant or planning to become pregnant. Olsalazine may pass into breast milk, so breastfeeding mothers should also seek medical advice before using this medication. Your doctor will evaluate the benefits of continued treatment against any potential risks.
Both Dipentum (olsalazine) and sulfasalazine are aminosalicylate medications used to treat ulcerative colitis. The key difference is their chemical structure: sulfasalazine combines 5-ASA with a sulfonamide (sulfapyridine), which is responsible for many of its side effects including headache, nausea, and allergic reactions. Dipentum consists of two molecules of 5-ASA linked together without any sulfonamide component, making it a better choice for patients with sulfonamide intolerance or allergy.
Dipentum has no known effect on the ability to drive or operate machinery. However, individual responses to any medication can vary. If you experience side effects like dizziness or headache, you should avoid driving or performing tasks that require full alertness until you know how the medication affects you personally. Consult your doctor if you have concerns.
References
- European Medicines Agency (EMA). Dipentum (olsalazine sodium) — Summary of Product Characteristics. Available at: ema.europa.eu/en/medicines/human/referrals/dipentum. Accessed February 2026.
- U.S. Food and Drug Administration (FDA). Dipentum (olsalazine sodium) Capsules — Prescribing Information. Approved 1990, updated 2023.
- Feagan BG, Macdonald JK. Oral 5-aminosalicylic acid for maintenance of remission in ulcerative colitis. Cochrane Database Syst Rev. 2012;(10):CD000544. doi:10.1002/14651858.CD000544.pub3
- Harbord M, Eliakim R, Bettenworth D, et al. Third European Evidence-based Consensus on Diagnosis and Management of Ulcerative Colitis. Part 2: Current Management. J Crohns Colitis. 2017;11(7):769-784. doi:10.1093/ecco-jcc/jjx009
- Ko CW, Singh S, Feuerstein JD, et al. AGA Clinical Practice Guidelines on the Management of Mild-to-Moderate Ulcerative Colitis. Gastroenterology. 2019;156(3):748-764. doi:10.1053/j.gastro.2018.12.009
- Rubin DT, Ananthakrishnan AN, Siegel CA, et al. ACG Clinical Guideline: Ulcerative Colitis in Adults. Am J Gastroenterol. 2019;114(3):384-413. doi:10.14309/ajg.0000000000000152
- World Health Organization (WHO). International Classification of Diseases, 11th Revision (ICD-11). Ulcerative colitis classification and coding.
- Egan LJ, Mays DC, Huntoon CJ, et al. Inhibition of interleukin-1-stimulated NF-kappaB RelA/p65 phosphorylation by mesalamine is accompanied by decreased transcriptional activity. J Biol Chem. 1999;274(37):26448-26453.
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This article was written and reviewed by the iMedic Medical Editorial Team, comprising licensed specialists in gastroenterology, pharmacology, and clinical medicine. Our content follows the GRADE evidence framework and is based on peer-reviewed research, international clinical guidelines (EMA, FDA, ACG, ECCO), and established medical standards.
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