DIPENTUM

What it is

DIPENTUM is a medicine containing olsalazine sodium. It is available as capsules containing 250 mg of olsalazine sodium and tablets containing 500 mg of olsalazine sodium. Olsalazine consists of two molecules of 5-amino-salicylic acid covalently bound through an azo-bond and is activated exclusively in the colon, where colonic bacterial azoreductases split the azo-bond to convert olsalazine into 5-ASA, the clinically active moiety.

Approved indications

— Treatment of ulcerative colitis in patients intolerant of sulphasalazine.

Dosing overview

DIPENTUM should be taken at regular intervals during the day, after meals. For acute ulcerative colitis using capsules, treatment should commence with 250 mg on the first day, gradually increasing by 250 mg daily to 2 g per day in divided doses; for tablets, treatment should commence with 500 mg on the first day, gradually increasing by 500 mg daily to 2 g per day in divided doses. If no response is achieved with 2 g and the medicine is well tolerated, the total dose may be increased to 3 g per day. A single dose should not exceed 1 g.

Key safety warnings

It is recommended to monitor renal function in patients receiving olsalazine by estimating serum creatinine before treatment, every 3 months for the first year, every 6 months for the next 4 years, and annually after 5 years of treatment. Although rare, blood dyscrasias may develop during therapy, and practitioners should be prepared to cease treatment immediately. Patients or their carers should be instructed how to recognise signs of haematotoxicity and should be advised to contact their treating doctor immediately if symptoms such as fever, sore throat, mouth ulcers, bruising, or bleeding develop. About 17% of subjects receiving DIPENTUM during clinical studies reported diarrhoea during therapy, and this diarrhoea resulted in withdrawal of treatment in 6% of patients. Patients who experience dose-related watery diarrhoea, particularly those with extensive disease at the initiation of treatment, may be managed by dosage reduction, and experience has shown that subsequent small incremental doses taken directly after meals are often well tolerated in these patients. Patients suffering from severe allergy or asthma should be observant to signs of worsening of these conditions. Regular monitoring of renal function in the elderly is advisable as renal function deteriorates with age.

Contraindications

DIPENTUM is contraindicated in patients with known hypersensitivity to salicylates or to any other constituents in DIPENTUM, pathological bleeding tendency, peptic ulcer, erosive gastritis, and in patients taking concomitant anticoagulants.

PBS listing

The 250 mg capsule and 500 mg tablet formulations are each listed on the PBS with streamlined restrictions. The ex-manufacturer price for the 250 mg capsule is A$29.38 and for the 500 mg tablet is A$51.75.

Regulatory history

DIPENTUM 250 mg capsule was first listed on the ARTG on 5 September 1991, and the 500 mg tablet formulation was first listed on 28 September 1995. The product was first approved on 14 September 1995.