5-Aminosalicylic Acids

Page last updated: 2 March 2018

Drug utilisation sub-committee (DUSC)

September 2017



At its June 2017 meeting, DUSC considered an analysis of utilisation of medicines to treat ulcerative colitis (UC). DUSC requested further analyses to determine if the increasing use of 5‑aminosalicylic acids (5-ASAs) is due to more patients being treated or patients using higher doses.

Listing on the Pharmaceutical Benefits Scheme (PBS)

5-aminosalicylates (sulfasalazine, mesalazine, balsalazide and olsalazine) are listed on the PBS in a range of oral and rectal formulations.

Restrictions apply to some of these medicines. See pbs.gov.au for details.

Data Source

The medicines included in the analysis were sulfasalazine, mesalazine, balsalazide and olsalazine. The analyses used data from the Department of Human Services (DHS) supplied prescriptions database for dates of supply between 1 January 2002 and 31 March 2017 inclusive. DHS Authorities data was used to examine prescriptions with an approved Authority for an increase in quantity or the number of repeats.

Utilisation was expressed as prescription volumes, DDD/1000 population/day and patient counts. The average daily amount (mass) of oral mesalazine dispensed per person was also calculated for 2007 and 2016.

Key Findings

  • The increasing utilisation of 5-ASAs is driven by growth in both the number of people on treatment and the amount of medicine dispensed per person.
  • Comparing 2007 with 2016 there was:
    • no change in the number of patients initiating a 5-ASA for the first time
    • a 27% increase in the number of patients on 5-ASAs (prevalent patients)
    • a 38% increase in prescription volume
    • a 42% increase in  DDDs/1000 population/day
  • The most commonly used 5-ASA is mesalazine. The average amount of mesalazine dispensed per patient per day increased by over 50% between 2007 and 2016.
  • The PBS dataset does not contain information on the prescribed dose or indication. Inference from the available data is difficult because of the individualisation of treatment, wide ranges of recommended doses, and different doses for induction and maintenance treatment. The use of higher doses is likely be a key factor contributing to the overall increase in use. Another factor could be improved adherence.

Full Report