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Generic Name: Balsalazide sodium
Product Name: Colazide

Indication: What Colazide is used for

Colazide is a drug used to treat acute attacks of a condition called ulcerative colitis and for long-term maintenance therapy to prevent attacks. It is used in patients who cannot tolerate sulfasalazine which is the usual medication for this disorder.

Ulcerative colitis is a condition in which there is inflammation of the large intestine. It is a sub-category of inflammatory bowel disease (which also includes Crohn’s disease). Ulcerative colitis causes ulceration and bleeding in the intestine and causes symptoms of abdominal pain and diarrhoea which may contain blood, pus or mucous. Colazide acts to reduce the swelling and irritation of the bowel wall to treat and prevent ulcerative colitis.

Your doctor will be able to explain if and why this medication is suitable for you.

Action: How Colazide works

Colazide contains balsalazide sodium, which belongs to a class of medicines called aminosalicylates. The actual drug consists of another drug called mesalazine linked to a carrier molecule with a special chemical bond.

When ingested, the balsalazide travels through the gastrointestinal tract until it comes to the colon (which is the site of disease). The colon contains lots of bacteria which break down the drug and release the mesalazine (the active medicine). This ensures that the drug reaches the site it is needed most.

Mesalazine works be reducing inflammatory of the mucosa (lining) of the colon. By damping down the inflammatory process and irritation, it allows the damaged tissue to recover. The exact mechanism it achieves this in not known. However trials have proven that this medication is effective at reducing symptoms of ulcerative colitis and improving healing of the mucosa as seen by sigmoidoscopy.

Dose advice: How to use Colazide


You should not take Colazide in the following circumstances:

  • If you are allergic to Colazide or any of the ingredients listed below. If you have hypersensitivity to aspirin-like products you should also not take this medication.
  • If you have a tendency to bleeding or are taking anti-bleeding medications. Colazide can disturb your blood counts and predispose to bleeding.
  • If you have an active peptic ulcer.
  • If you have severe liver problems or kidney problems.
  • If you are in the late stages of pregnancy. Colazide can prolong labour and cause bleeding problems in yourself and your baby so should not be taken in the last few weeks of pregnancy. You should discuss the pros and cons of treatment with your doctor if you are in the earlier stages of pregnancy of if you intend to become pregnant.
  • If you are breastfeeding. Some of your dose of Colazide can be transferred to your baby via your milk which may cause side effects.

In addition, you should let your doctor know if you have any allergies to medicines, foods, dyes or preservatives or if you have any other medical problems, in particular any mild liver problems, asthma, kidney problems, stomach ulcer or bleeding problems.

You should tell your doctor all other medications you are taking (including any bought over the counter) as Colazide may interact with other medications.

Product description

Colazide comes as beige capsules containing 750mg of the active component balsalazide as well as some inactive ingredients including magnesium stearate, silica-colloidal anhydrous, gelatin and shellac.

The capsules are supplied in bottles of 180 capsules. The capsules are intended to be swallowed whole and you should take them with some food.


The usual doses of Colazide vary depending on the indication for treatment.

If it is being used to treat active disease, you will need to take three capsules, three times a day (total of 9 tablets daily) until your symptoms improve. You should not take Colazide for longer than 12 weeks unless specifically told to do so by your doctor.

For maintenance therapy and preventing attacks of ulcerative colitis, a lower dose of two capsules, twice daily (total of 4 tablets daily) is usually recommended. Your doctor may adjust this according to your response and how well you tolerate the drug up to a maximum of 8 capsules daily.

In addition, you may also need to take other medications, such as steroids (by mouth or via the back passage) to further reduce the inflammation. Colazide can be used safely in conjunction with these medications.

Doses of Colazide are the same for adults and elderly patients. However, Colazide should not be used in children lass than 18 years of age.

If you miss a dose of Colazide and realise less than 4 hours before the next dose, just skip the missed dose and continue with your next doses as usual.

Note that the above is only a guide to the usual recommended doses of Colazide. You may be prescribed a slightly different dosing regimen due to differences in your disease, underlying health or tolerance to the medication. You should always take Colazide strictly as prescribed by your doctor.

Schedule of Colazide

Schedule 4 (prescription only). PBS authority scripts are required for packets of 180 and repeat scripts. The approved indications for authority include:

  • Ulcerative colitis where hypersensitivity to sulfonamides exists
  • Ulcerative colitis where intolerance to sulfasalazine exists

Side effects of Colazide

Common side effects

Colazide is well tolerated in most patients but like any other medication has the potential to cause side effects. Most of the side-effects are mild and only last for a short period of time, while the body gets used to the drug. Others are more serious and require urgent medical attention (as listed below). In general side effects are more common if you are taking higher doses of Colazide.

If you experience any of the following side-effects that are worrying you, do not hesitate to discuss them with your doctor. Note that the following lists of side-effects are not necessarily exhaustive as new side effects can be discovered as more patients use the drug. If you have any symptoms that you think may be caused by this medication be sure to let your doctor know.

The most common side effects of Colazide include:

  • Headache (approximately 7% of patients);
  • Abdominal pain (approximately 6% of patients);
  • Diarrhoea (approximately 5% of patients);
  • Nausea and vomiting (approximately 3% of patients);
  • Flu-like symptoms or other respiratory illness;
  • Fatigue;
  • Anorexia (loss of appetite);
  • Back pain;
  • Dizziness;
  • Aggregation of ulcerative colitis;
  • Constipation;
  • Fever;
  • Insomnia;
  • Malaena (black tarry stools);
  • Dry mouth;
  • Myalgia (muscle weakness);
  • Rhinitis (hayfever-like symptoms);
  • Itching.

All these side effects occurred in at least one in every 100 patients taking Colazide in clinical trials.

Uncommon side effects

More serious side effects are uncommon and occur in less than 1% of patients. However it is important that you are aware of them so if they occur you can get urgent medical care.

You should look out for any symptoms of any of the following:

  • Interstitial nephritis (inflammation of the kidney) – You may notice a change in your urine output, blood in the urine, fever or swelling elsewhere in the body.
  • Allergic reactions – As previously mentioned, it is important you tell your doctor of any allergies you have prior to taking this medication so that allergic reactions can be prevented. If you develop rash, itching or hives, swelling of the face, lips and tongue (angioedema), shortness of breath, wheezing or difficulty breathing whilst taking this medication you may be experiencing an allergic reaction and require urgent treatment.
  • Kidney stones;
  • Disturbed blood counts – Reduced red blood cells can cause anaemia making you pale, tried and lethargic. If your platelet count drops you may notice easy bruising or bleeding. Reduced leukocytes (white blood cells) can predispose to infection so any fever whilst taking Colazide should be treated seriously.
  • Pancreatitis (inflammation of the pancreas).
  • Hepatitis (inflammation of the liver).

If these side effects occur you need to see a doctor or go to the emergency department immediately as some of them can be life-threatening. Fortunately however these side effects are all rare.


  1. Australian Medicines Handbook- 12.6.2 Balsalazide, AMH Pty Ltd. 2007.
  2. Colazide (R), Balsalazide sodium capsules- Consumer Medicine Information, Pharmatel Fresenius Kabi Pty Ltd. 2004.
  3. Colazide (R)- Product Information, Pharmatel Fresenius Kabi Pty Ltd. 2007.
  4. MIMS online- Prescribing Information, Balsalazide sodium, MIMS Australia Pty Ltd 2003.

For further information talk to your doctor.

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Posted On: 23 November, 2005
Modified On: 13 March, 2018
Reviewed On: 29 June, 2007

Created by: myVMC