Colazal Patient Tips

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on June 7, 2025.

1. How it works

• Colazal (generic name: balsalazide) is an oral prescription medicine approved by the FDA for the treatment of mildly to moderately active ulcerative colitis in patients 5 years of age and older. It helps to lower inflammation.
• Safety and effectiveness beyond 8 weeks in pediatric patients 5 years to 17 years of age and 12 weeks in adults have not been established.
• Colazal, an aminosalicylate, is used to treat ulcerative colitis and contains balsalazide disodium, a prodrug. Prodrugs are inactive when first taken. Once they are in your system, they are converted to an active medication.
• When taken orally, Colazal is delivered to the colon where it releases mesalamine (5-ASA), the active drug. The mechanism of 5-ASA is not fully understood, but may act locally by blocking production of arachidonic acid metabolites to lower inflammation.
• Ulcerative colitis is a long-term inflammatory bowel disease of the colon (the large intestine). Inflammation and ulcers form on the inner lining of the colon. Common symptoms include: diarrhea with blood or mucus, bleeding from the rectum, urgent need to have a bowel movement, stomach pain, fever, poor appetite, weight loss, and fatigue.
• Colazal is made by Salix Pharmaceuticals.

2. Upsides

• Colazal capsules can be used in adults and children 5 years of age and older. You can take Colazal with or without food. Swallow capsules whole. Do not cut, break, crush or chew.
• If you cannot swallow intact capsules, you may open the capsule and sprinkle the contents on 2 teapsoonfuls (10 mL) of applesauce, then eat and swallow it immediately. You may chew the mixture if needed. Note that the color of the powder inside may vary from orange to yellow and this is expected.
• Oral doses are taken for up to 8 weeks in children and for 8 to 12 weeks in adults. In studies, the number of adults who stopped therapy because of side effects was similar to those patients taking a placebo (an inactive treatment). It appears to be well-tolerated by most patients.
• The generic version of Colazal (known as balsalazide) may save you money at the pharmacy if you are paying with cash, have no insurance or have a high copay. Ask your doctor for the generic version, if you prefer, and talk to your pharmacist about the pricing for Colazal or balsalazide.
• Colazal capsules can be stored at room temperature (20 to 25 degrees C, or 68 to 77 degrees F).

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

• Headache, stomach-area pain, diarrhea, nausea, vomiting, respiratory infection and arthralgia (joint pain) are the most common side effects (≥3%) in both adults and children.
• It is not known if Colazal use is safe or effective in children (5 to 17 years of age) beyond 8 weeks of treatment, or beyond 12 weeks in adults.
• May cause kidney problems, especially in people taking drugs that are toxic to the kidney like NSAIDs (for example: ibuprofen like Motrin or Advil; naproxen like Aleve or Naprosyn; indomethacin; others) or in people that already have kidney disease. May also cause kidney stone formation. Patients should drink plenty of fluids during treatment.
• May cause serious liver failure in patients with pre-existing liver disease.
• Can cause Acute Intolerance Syndrome to mesalamine that may be difficult to distinguish from a worsening of ulcerative colitis. In some mesalamine studies, this side effect has occurred in up to 3% of patients.
• Some people may experience a hypersensitivity reaction (allergy) to mesalamine. These may present as types of organ inflammation such as with the heart, kidney, liver, lungs or blood systems.
• Patients taking certain medicines (azathioprine, 6-mercaptopurine or other drugs that can cause bone marrow toxicity, especially those 65 years of age and older (geriatric patients), may develop blood disorders or complications and need period monitoring of their complete blood cell counts and platelets.
• Colazal may cause serious allergies in people allergic to aminosalicyates or salicylates, like aspirin or other salicylates (including Kaopectate, Pamprin, Pepto-Bismol, Tricosal, Trilisate, and others).
• Severe, possibly fatal skin reactions may occur with the use of Colazal. Possible skin reactions include: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP).
• While taking Colazal, you may need to avoid sun exposure, wear protective clothing, and use a broad-spectrum sunscreen when outdoors. People that have eczema have reported more severe skin reactions when in the sun.
• If you are at risk of an upper gastrointestinal obstruction, such as pyloric stenosis, you may not be able to use Colazal. This may cause you to retain the medicine in your digestive tract and the active ingredient may not be released in your colon.
• If you take too much Colazal you may be at risk for salicylate toxicity, which may include: nausea, vomiting and abdominal pain, fast or deep breathing, ringing in your ears, and neurologic symptoms (headache, dizziness, confusion, seizures), electrolyte and blood pH imbalance and organ damage (such as the kidneys and liver).
• If you sprinkle Colazal on applesauce before taking it (instead of swallowing the capsule) it may cause your teeth and tongue to become stained.
• The Colazal brand name product is expensive and your insurance may only pay for the generic version.
• This is not a complete list of all of the possible side effects or warnings with Colazal. Call your doctor for medical advice about side effects.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

Colazal (generic name: balsalazide) is an oral prescription medicine indicated for the treatment of mildly to moderately active ulcerative colitis in people 5 years of age and older. It is classified as an aminosalicylate and is converted to mesalamine, the active drug, in the colon where it has its effect.

5. Tips

• Follow any medicine directions on your package. Tell your healthcare providers about all your medical conditions, allergies, and all medicines you use, including any over-the-counter (OTC), vitamin or herbal products.
• Tell your healthcare provider if you have ever had kidney disease, liver disease, a stomach condition called pyloric stenosis or take drugs that are toxic to the kidney. Tell your doctor if you have, or are at risk of, a gastric obstruction. Symptom may include stomach area pain, vomiting, feeling full quickly when eating, and weight loss.
• Be sure to complete any laboratory tests ordered by your healthcare provider. Your kidney function will be looked at before you start treatment with a blood test. Your doctor may need to further monitor your kidneys, liver and blood cell counts to help prevent side effects. If your kidney function declines, your doctor may need to adjust your dose or stop treatment.
• Tell your laboratory technician that you take Colazal before any laboratory tests, as this medicine may interfere with some tests.
• Swallow Colazal capsules whole. Do not cut, break, crush or chew the capsules. If you open the capsule and mix it with applesauce, do not save the mixture for later use. Color variation of the powder inside the capsules ranges from orange to yellow.
• To mix Colazal in applesauce: Place a small amount (approximately 10 mL) of applesauce into a clean container. Carefully open the capsules. Sprinkle the capsule contents on the applesauce. Mix the capsule contents with the applesauce. The contents may be chewed, if necessary. Consume the entire amount of applesauce mixture immediately. Do not store the applesauce mixture for future use.
• You can take Colazal with or without food.
• If you miss a dose, take it as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.
• Drink an adequate amount of fluids with Colazal to decrease your risk for kidney stone formation. Contact your healthcare provider if you have signs or symptoms of a kidney stone, such as severe side or back pain, blood in the urine, or vomiting, fever or chills.
• If you have signs or symptoms of liver disease, such as nausea, upper abdominal pain or swelling, yellow eyes / skin (jaundice), dark-colored urine, itchy skin, or pale-colored stools, contact your healthcare provider.
• If you are taking Colazal, urine may change to a reddish-brown color when it comes in contact with surfaces or water treated with hypochlorite-containing bleach. If you see discolored urine, observe your urine flow. Call your healthcare provider only if urine is discolored on leaving the body, before contact with any surface or water (e.g., in the toilet).
• Stop taking Colazal and contact your healthcare provider right away if you have new or worsening symptoms of cramping, abdominal pain, bloody diarrhea, fever, headache, rash. You may be experiencing Mesalamine-Induced Acute Intolerance Syndrome that may be difficult to distinguish from a worsening of ulcerative colitis. Your doctor may decide to stop your treatment with Colazal.
• Some people may experience a hypersensitivity reaction (allergy) to mesalamine. These may present as types of organ inflammation such as with the heart, kidney, liver, lungs or blood systems. Contact your doctor right away, or get emergency help, if you experience chest pain or pressure, cloudy changes in urine, edema or swelling, high blood pressure, fatigue, headaches, jaundice (yellowing of painful urination, skin or eyes), pale-colored stools, nausea, vomiting, flu-like symptoms, loss of appetite, shortness of breath, dry cough, fever, weakness, bruising or bleeding or frequent infections.
• Tell your doctor if you are pregnant or planning a pregnancy. It is not known whether Colazal will harm an unborn baby. You and your doctor can make a shared decision about use of Colazal during pregnancy.
• Colazal has been shown to get into breast milk in very small amounts. There is no information on the effects of the drug on milk production. You and your healthcare provider will determine if the benefits of breastfeeding outweight any risks of Colazal to you or your baby. There are case reports of diarrhea in breastfed infants exposed to mesalamine. If you are breastfeeding while taking Colazal, tell your doctor if you notice diarrhea in your baby.
• Do not use Colazal if you have a known or suspected allergic reaction to balsalazide, Colazal, mesalamine (Apriso, Pentasa) or balsalazide metabolites, aspirin or other salicylates or aminosalicylates (may include Kaopectate, Pamprin, Pepto-Bismol, Tricosal, Trilisate, Doan's pills, bismuth subsalicylate, choline magnesium trisalicylate, choline salicylate, diflunisal, magnesium salicylate, salsalate, sulfasalazine (Azulfidine) and others), or any of the components of Colazal capsule. If you are not sure, ask your pharmacist or other healthcare provider for a list of ingredients.
• Get emergency medical help (call 911 in the U.S.) if you have signs of an allergic reaction such as hives, difficulty breathing, or swelling of your face, lips, tongue, or throat.
• Tell your doctor if you have a history of eczema (atopic dermatitis). While taking Colazal, avoid sun exposure, wear protective clothing, and use a broad-spectrum sunscreen when outdoors. This medicine may also lead to severe skin reactions (hypersensitivity reactions / allergies). If you experience any severe skin side effects, stop use of this drug and call your doctor or 911 right away. Your doctor may need to stop your treatment. You may experience skin rash, blisters, peeling skin, swelling or other symptoms. Ask your doctor how to recognize severe skin reactions.
• Excessive doses of Colazal may lead to salicylate toxicity like: nausea, vomiting and stomach pain, fast or deeper breathing, ringing in ears, and neurologic symptoms such as headache, dizziness, confusion, electrolyte and blood pH imbalance, organ damage (like kidney or liver) and seizures. If you have taken too much Colazal, seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

6. Response and effectiveness

Adults

• In adults in a clinical study over an 8-week period, 103 patients with active mild-to-moderate ulcerative colitis with bleeding were treated with 6.75 grams (g) per day or 2.25 g per day of balsalazide (Colazal).
• Researchers assessed whether treatment led to a reduction in rectal bleeding and improvement in at least one of the following: stool frequency, patient functional assessment, abdominal pain, sigmoidoscopic grade, and physician’s global assessment.
• Results showed a significant difference between high and low doses of Colazal, which means the positive outcomes at the higher dose did not occur just by chance. A second study in Europe confirmed these results.

Children (5 to 17 years of age)

• In an 8-week clinical study in children with mildly to moderately active ulcerative colitis, 68 children 5 to 17 years of age received either 6.75 g per day or 2.25 g per day of Colazal.
• Fifteen (45%) patients in the Colazal 6.75 g per day group and 13 (37%) patients in the Colazal 2.25 g per day group showed this clinical improvement (based on a 3-point improvement on the Modified Sutherland Ulcerative Colitis Activity Index (MUCAI).
• Rectal bleeding improved in 64% of patients treated with Colazal 6.75 g per day and 54% of patients treated with Colazal 2.25 g per day.
• Colonic mucosal appearance upon endoscopy improved in 61% of patients treated with Colazal 6.75 g/day and 46% of patients treated with Colazal 2.25 g/day.

7. Interactions

Medicines that interact with Colazal may change its effects, affect how long it works, or increase side effects. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

• NSAIDs and other medicines toxic to the kidney: May increase the risk of kidney disease when used with Colazal. If needed, your doctor will monitor your kidney function. Tell your doctor if you take NSAIDS like ibuprofen or naproxen before you start treatment with Colazal.
• Azathioprine, 6-mercaptopurine and / or any other drugs known to cause blood toxicity (myelotoxicity): may increase the risk for blood disorders, bone marrow failure, and associated complications. Your doctor may need to monitor blood cell and platelet counts.
• Laboratory test interference with urine normetanephrine measurements (normetanephrine is a marker for catecholamine-secreting tumors such as pheochromocytoma): May lead to false elevated test results when measuring urinary normetanephrine by liquid chromatography with electrochemical detection. Consider an alternative, selective assay for normetanephrine.
• Ask your doctor before using balsalazide together with varicella virus vaccine (chicken pox vaccine). Using these medications together may be associated with Reye's syndrome, a sudden, sometimes fatal, disease of the brain with degeneration of the liver and occurs in children. If you are receiving varicella virus vaccine and less than 18 years of age you should avoid the use of balsalazide for 6 weeks after immunization with varicella virus vaccine.
• Do not stop using any medications without first talking to your doctor.

Note that this list is not all-inclusive and includes only common medications that may interact with Colazal. You should refer to the prescribing information for a complete list of interactions. Tell your doctor and pharmcist about all your current medicines and any medicine you start or stop using.

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Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Colazal only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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