Readers are invited to write in with their questions about decisions of the Pharmaceutical Benefits Advisory Committee (PBAC). Australian Prescriber publishes selected questions from readers, together with answers from the PBAC. Questions may address issues such as regulatory decisions, pharmaceutical benefits listings and withdrawals.

This exclusive arrangement helps Australian Prescriber readers understand how the contents of the Pharmaceutical Benefits Scheme (PBS, see are determined.

Letters and responses are reviewed by the Editorial Executive Committee and may be edited before publication. It may not be possible to reply to all individual questions.

Your questions to the PBAC

During my research for a presentation on managing constipation and the use of laxatives in the aged-care setting for our local nursing home, I consulted published guidelines and other references for information. My search also included the Schedule of Pharmaceutical Benefits. It was then that I became aware just how difficult it is for prescribers to follow guidelines in this area. Stimulant laxatives (such as bisacodyl) are covered quite comprehensively, despite being considered as third- or fourth-line agents by the guidelines. Bulking agents and osmotic agents are poorly covered in the Schedule, but are listed as first- or second-line treatments in most of the references I consulted. This anomaly has resulted in the common use of stimulant laxatives at our facility (and, I suspect many others) when non-pharmacological interventions have failed. Can the PBAC consider widening the restrictions on these agents, particularly lactulose, to include residents of aged-care facilities? Ease of use makes lactulose especially attractive.

A laxative-free nursing home may be a dream, but a stimulant-free one may be achievable!

Alison Hilet
Moama, NSW

PBAC response:

The Pharmaceutical Benefits Advisory Committee (PBAC) is legally required, in evaluating applications for Pharmaceutical Benefits Scheme (PBS) subsidy, to take into account the clinical effectiveness, safety and cost-effectiveness (value for money) of the medication concerned compared to other available therapies.

Importantly, a medicine cannot be subsidised via the PBS unless the PBAC makes a positive recommendation. In other words, a decision by the Committee not to recommend a medicine be subsidised is binding on the Government.

The PBAC has considered the listing of lactulose for the treatment of patients in domiciliary or nursing home care in the past. However, the PBAC was of the opinion that lactulose is an expensive synthetic disaccharide which is no more effective than other cheaper osmotic laxative preparations, and it is associated with abdominal discomfort in a number of patients. The Committee felt that further widening the indication would encourage unnecessary and definitely non-cost-effective use.

The PBAC is reluctant to recommend laxative products for listing on the PBS and considers that other measures such as modification of diet can be used in the treatment of constipation in most patients.