Estimating the utilisation of unregistered antimicrobials in Australia.

Abstract

To identify and estimate the usage of unregistered antimicrobial drugs in Australian clinical practice. A descriptive pharmaco-epidemiological study, utilising three data sources: analysis of Special Access Scheme (SAS) applications for unregistered antimicrobials included in clinical guidelines over a five year period, analysis of antimicrobials dispensed from South Australian public hospital pharmacy departments over a two year period and analysis of National Antimicrobial Utilisation Surveillance Program (NAUSP) data for reported inpatient usage of unregistered antimicrobials in Australian hospitals over the last 5 years. 59 unregistered antimicrobials were identified using the mixed methods. 18,362 Special Access Scheme applications were submitted between May 2012 and April 2017 to access the 20 unregistered antimicrobials identified in the Therapeutic Guidelines® (eTG complete); 51.4% were determined by the prescriber to be for life-threatening indications. Annual applications more than doubled over the five years. 34 unregistered antimicrobials were dispensed from South Australian public hospitals between July 2015 and June 2017. On average, 1.1% of total antimicrobial usage (Defined Daily Doses) per month was accessed via the SAS, of which 87.7% were for outpatients or discharged patients. 34 unregistered antimicrobials for systemic use identified in the NAUSP database were used in Australian hospitals between 2013 and 2018. The use of unregistered antimicrobials in Australian clinical practice is not uncommon. With increasing antimicrobial resistance, there will be a continued reliance on older less-used antimicrobial agents and an increasing need for novel drugs, therefore regulatory pathways need to facilitate security of supply and assurance of medicine quality and safety.