Australian GPs are prescribing between four and nine times as many antibiotics for certain infections as they should.

A new study - the first to quantify Australian overprescription of antibiotics - found that, if national guidelines were followed, the rate of prescriptions would drop by 77 to 89 per cent.

The authors say antibiotics are prescribed for 85 per cent of acute bronchitis/bronchiolitis cases, despite not being recommended in the guidelines at all, and for 11 per cent of influenza cases, where antibiotics are useless because flu is a viral rather than a bacterial infection. 

Antibiotics are always recommended for community-acquired pneumonia (current prescribing rate, 72 per cent) and pertussis (71 per cent), as well as for 0.5–8 per cent of cases of acute rhinosinusitis (current prescribing rate, 41 per cent), 20–31 per cent of cases of acute otitis media (89 per cent), and 19–40 per cent cases of acute pharyngitis or tonsillitis (94 per cent).

“Had GPs adhered to the guidelines, they would have prescribed antibiotics for 0.65–1.36 million ARIs [acute respiratory infections] per year nationally, or at 11–23 per cent of the current prescribing rate,” the authors wrote.

“Antibiotics were prescribed more frequently than recommended for acute rhinosinusitis, acute bronchitis/bronchiolitis, acute otitis media, and acute pharyngitis/tonsillitis.

“Diagnostic uncertainty — concern by the treating doctor that a serious infection or complications might be missed — is one potential explanation for this finding,” the authors wrote.

Antimicrobial drug resistance is a global problem, and reducing antibiotic use is the most important clinical response, according to national and international guidelines on antimicrobial stewardship.

“The potential for reducing rates of antibiotic prescription and to thereby reduce rates of antibiotic-related harms, particularly bacterial resistance, is … substantial,” lead researcher Christopher Del Mar, Professor of Public Health at Bond University and his colleagues concluded.

“Our data provide the basis for setting absolute targets for reducing antibiotic prescribing in Australian general practice.”