Colazal Side Effects

Generic name: balsalazide

Medically reviewed by Philip Thornton, DipPharm. Last updated on Feb 26, 2025.

Note: This document provides detailed information about Colazal.

Applies to balsalazide: oral capsule Side Effects associated with balsalazide. Some dosage forms listed on this page may not apply specifically to the brand name Colazal.

Applies to balsalazide: oral capsule.

Precautions

It is important that your doctor check your progress at regular visits. This will allow your doctor to see if this medicine is working properly and to decide if you should continue to take it. Blood and urine tests may be needed to check for any unwanted effects.

If your symptoms do not improve or if they become worse, check with your doctor.

This medicine may cause serious kidney problems, including kidney stones. Check with your doctor right away if you have lower back or side pain, decreased frequency or amount of urine, bloody urine, increased thirst, loss of appetite, nausea, vomiting, unusual tiredness or weakness, swelling of the face, fingers, or lower legs, weight gain, or trouble breathing.

Check with your doctor right away if you have stomach pain, bloody diarrhea, cramps, fever, headache, or a rash while you are using this medicine. These may be symptoms of a condition called mesalamine-induced acute intolerance syndrome.

Call your doctor right away if you have difficulty breathing or swallowing, a fast heartbeat, itching, rash, or skin redness, or swelling of the face, throat, or tongue. These may be symptoms of an allergic reaction to this medicine.

This medicine may cause serious skin reactions, including Stevens-Johnson syndrome, toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP). Check with your doctor right away if you have black, tarry stools, blistering, peeling, or loosening of the skin, chest pain, chills, cough, diarrhea, itching, joint or muscle pain, painful or difficult urination, red irritated eyes, red skin lesions, often with a purple center, sore throat, sores, ulcers, or white spots in the mouth or on the lips, swollen glands, trouble breathing, unusual bleeding or bruising, or unusual tiredness or weakness.

Check with your doctor right away if you have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, vomiting, or yellow eyes or skin. These could be symptoms of a serious liver problem.

This medicine may make you more sensitive to light and cause serious unwanted skin reaction. This is more likely if you have an existing skin problem (eg, atopic dermatitis, atopic eczema). Check with your doctor right away if you have increased sensitivity of the skin to sunlight, itching, redness or other discoloration of the skin, severe sunburn, or skin rash. Use a sunscreen when you are outdoors. Avoid sunlamps and tanning beds.

Make sure any doctor or dentist who treats you knows that you are using mesalamine. This medicine may affect the results of certain medical tests.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Serious side effects of Colazal

Along with its needed effects, balsalazide (the active ingredient contained in Colazal) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking balsalazide:

Other side effects of Colazal

Some side effects of balsalazide may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

For healthcare professionals

Applies to balsalazide: oral capsule, oral tablet.

Gastrointestinal adverse events

• Very common (10% or more): Abdominal pain upper (17%), vomiting (17%), abdominal pain (12%), diarrhea (11%)
• Common (1% to 10%): Flatulence, dyspepsia, dry mouth, constipation, colitis ulcerative, hematochezia, nausea, stomatitis
• Frequency not reported: Defecation urgency, hard feces, gastroesophageal reflux disease, gastroenteritis
• Postmarketing reports: Pancreatitis^[Ref]

Nervous system

• Very common (10% or more): Headache (15%)
• Frequency not reported: Dizziness, lethargy^[Ref]

Other

• Very common (10% or more): Pyrexia (11%)
• Common (1% to 10%): Fatigue, fever, flu-like disorder, pyrexia
• Frequency not reported: Malaise, pain, pyrexia^[Ref]

Musculoskeletal

• Common (1% to 10%): Arthralgia, musculoskeletal pain, myalgia, cramps
• Frequency not reported: Back pain^[Ref]

Respiratory

• Common (1% to 10%): Pharyngolaryngeal pain, coughing
• Postmarketing reports: Alveolitis, pleural effusion^[Ref]

Hepatic

• Frequency not reported: Increased aspartate aminotransferase
• Postmarketing reports: Elevated liver enzymes (AST, ALT, GGT, LDH, alkaline phosphatase), elevated bilirubin, jaundice, cholestatic jaundice, cirrhosis, hepatocellular damage including liver necrosis and liver failure, Kawasaki-like syndrome including hepatic dysfunction^[Ref]

Hematologic

• Common (1% to 10%): Anemia^[Ref]

Cardiovascular

• Frequency not reported: Increased blood pressure, increased heart rate
• Postmarketing reports: Myocarditis, pericarditis, vasculitis^[Ref]

Renal

• Postmarketing reports: Renal failure, interstitial nephritis^[Ref]

Dermatologic

• Frequency not reported: Erythema nodosum, rash, face edema
• Postmarketing reports: Alopecia, pruritus^[Ref]

Immunologic

• Common (1% to 10%): Nasopharyngitis, rhinitis, pharyngitis, urinary tract infection, influenza
• Frequency not reported: Upper respiratory infection
• Postmarketing reports: Pneumonia (with and without eosinophilia)^[Ref]

Metabolic

• Common (1% to 10%): Anorexia^[Ref]

Psychiatric

• Common (1% to 10%): Insomnia^[Ref]

Genitourinary

• Common (1% to 10%): Dysmenorrhea^[Ref]

See also:

Further information

Colazal side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer