More patients are starting on lower doses since the PBS changes.
The number of patients taking high-dose proton pump inhibitors (PPI) crashed after PBS changes made these formulations significantly harder to prescribe.
In 2017, one in four patients taking the common medication started on a high dose, according to the Drug Utilisation Sub-Committee (DUSC) of the Pharmaceutical Benefits Advisory Committee (PBAC).
By 2020, this proportion had dropped to one in 50. This was a decline from 146,000 patients down to only 8000.
The change comes after warnings from PBAC that high-dose PPIs were overprescribed, for excessively long periods of time and particularly among older people.
“The PBAC considered that this is not in the best interests of patients and is not without safety concerns,” it said in 2018. “The PBAC were particularly concerned by the large number of high and highest dose prescriptions dispensed (95%) relative to low dose PPIs (5%) across 2013-2016.”
In 2019, the PBS made a suite of changes to its PPIs listings, covering restriction levels, terminology, clinical criteria and the number of repeats patients could get.
At the time, the PBAC recommended that restriction levels be revised to increase awareness of the higher therapeutic relativity of esomeprazole 40mg compared with standard dose PPIs.
Overall, DUSC figures show that more than 600,000 patients were started on PPIs in 2017, but this dropped to under 500,000 by 2020.
The group’s analysis found a decline in defined daily doses for high-dose listings, as well as an overall reduction in defined daily doses following the restriction changes.
“Even though total script utilisation (across all drugs) increased after the May 2019 restriction changes, the total number of defined daily doses decreased indicating that patients were moving to lower dose PPIs,” the DUSC said in its June statement.
According to the Gastroenterological Society of Australia, PPIs have been linked to an increased risk of fractures, pneumonia, enteric infections, vitamin and mineral deficiencies, and acute interstitial nephritis, especially among older people.
In some studies, prolonged PPI use has been found to moderately increase the risk of colorectal cancer.
An observational study including data of more than 1.2 million people in the UK, published in Gut, found that short-term use did not cause a meaningful increase in the risk of colorectal cancer.
However, the risk of developing cancer increased with dosage and duration, the Canadian authors said.
The overall incidence of colorectal cancer diagnoses was 106 per 100,000 person-years among people newly treated with PPIs.
For patients with cumulative PPI use of four years or more, the incidence of colorectal cancer was 165 per 100,000 person-years.