Antibiotic switch during treatment with antibiotics against respiratory tract infections in ambulatory care in Norway

To compare antibiotic treatment failure evaluated as switch from one type of antibiotics to another in ambulatory care.Data on all dispensed doxycycline, amoxicillin, phenoxymethylpenicillin and macrolides in Norway June 2013 - May 2015, was retrieved from the Norwegian Prescription Database. We computed switch rates for the selected antibiotics on day 1-28 after initial dispensing, and the corresponding odds-ratios, adjusted for patients´ age and gender, and prescribers´ specialty.Of 1.860.036 dispensed antibiotics, 103.076 (5.5%) were switched within 28 days. Within 10 days after the index date, the switch rate was highest for phenoxymethylpenicillin (4.1%), followed by amoxicillin (2.5%), macrolides and doxycycline (2.2%).The switch rate after initial dispensing of phenoxymethylpenicillin is higher than that of more broad-spectrum antibiotics. However, it is still low, supporting the recommendation of phenoxymethylpenicillin as first line treatment when an antibiotic is indicated for a respiratory tract infection in primary care.