Some of the views expressed in the following notes on newly approved products should be regarded as preliminary, as there may have been limited published data at the time of publication, and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. Before new drugs are prescribed, the Committee believes it is important that more detailed information is obtained from the manufacturer's approved product information, a drug information centre or some other appropriate source.


Balsalazide sodium

Colazide (Pharmatel)
750 mg capsules
Approved indication: ulcerative colitis
Australian Medicines Handbook section 12.6.2

Mesalazine is an aminosalicylic acid derivative which has been used in the treatment of inflammatory bowel disease. Balsalazide is the prodrug of mesalazine. The active drug is released from balsalazide by bacterial enzymes in the colon.

Very little balsalazide is absorbed after oral administration. Mesalazine is absorbed, but is rapidly metabolised and excreted in the urine.

Balsalazide has been compared with mesalazine in a double-blind trial. Patients with acute ulcerative colitis were treated for up to 12 weeks. More patients taking balsalazide went into remission. At the end of the study 62% were in remission compared to 37% of the patients taking mesalazine.1

This trial continued as a study of balsalazide and mesalazine in maintenance treatment. Although 58% of both treatment groups were in remission after a year, fewer patients taking balsalazide relapsed in the first three months. They also had more symptom-free days and nights.2

The adverse effects of balsalazide and mesalazine are similar. During the study of acute ulcerative colitis only half the patients treated with balsalazide experienced adverse effects compared to 70% of the patients taking mesalazine.1 However, during maintenance treatment both drugs were associated with adverse effects in more than 60% of patients..

Adverse effects include headache, diarrhoea, nausea and vomiting. Balsalazide should not be given to patients who are allergic to salicylates. Any unexplained bleeding or bruising is an indication for a blood test to look for a blood dyscrasia.

The newer aminosalicylic acid derivatives were designed to overcome the problems associated with drugs such as sulfasalazine. A Cochrane review has, however, questioned if the newer drugs have a clinical advantage over sulfasalazine for inducing remission.3 Another Cochrane review has found that the newer drugs are inferior to sulfasalazine for maintenance treatment.4 The use of balsalazide is therefore restricted to patients who are intolerant of sulfasalazine.