Long-term antibiotic prescribing in the community: 6 years of Australian national data

Background: Prolonged or indefinite courses of antibiotics are sometimes prescribed for suppression of chronic infection, prophylaxis, and noninfective indications. Little is known about long-term prescribing practices in the community. In Australia, 75% of outpatient prescribing is funded through the Pharmaceutical Benefits Scheme (PBS), a government program for subsidized medications.

Objectives: To describe the landscape of outpatient prescribing of long-term antibiotics in Australia.

Methods: We descriptively analyzed a randomized 10% sample of PBS prescription data from 2014 to 2020. "Long term" was defined as continuous prescribing 12 months or more. Patients were identified using a rolling window algorithm with 12-month look-back from each script provided.

Results: Prolonged continuous antibiotics (> 12 months) were prescribed to 339/100,000 population; 50% of patients were aged more than 65 years and prescribing increased with age (1440/100,000 population in patients > 75 years). Frequently prescribed antibiotic classes were tetracyclines (43% of all long-term antibiotics), sulfonamides/trimethoprim (21%, predominantly cotrimoxazole), cephalosporins (15%, predominantly cefalexin), and penicillins (13%). Prophylaxis of infection and immunomodulatory indications were most common. Patients were co-prescribed analgesics (30%), antidepressants (30%), corticosteroids (20%), and immunosuppressive drugs (6%).

Conclusion: Prolonged community prescribing of antibiotics is an important target for antibiotic stewardship, particularly in older adults.