Longitudinal surveillance of outpatient tetracycline, sulfonamide-trimethoprim and 'other' antimicrobial use in Canada, 1995 to 2010.

INTRODUCTION

Monitoring the volume and patterns of use of antimicrobial agents is important in light of antimicrobial resistance.

OBJECTIVE

To assess the use of three antimicrobial groups - tetracycline, sulfonamide-trimethoprim and 'other' antimicrobials - within Canadian provinces over time.

METHODS

Prescription counts from 1995 to 2010 were acquired for the tetracycline and sulfonamide-trimethoprim groups of antimicrobials, and from 2001 to 2010 for the 'other' antimicrobial group. Linear mixed models were produced to assess differences among provinces and over time while accounting for repeated measurements. Prescription rate, defined daily dose per 1000 inhabitant-days and defined daily doses per prescription measures for the year 2009 were also compared with those reported by participating European Union countries to determine where Canadian provinces rank in terms of antimicrobial use among these countries.

RESULTS

Prescribing of all three groups varied according to province and over time. Tetracycline and sulfonamide-trimethoprim group prescribing were significantly reduced over the study period, by 36% and 61%, respectively. Prescribing of the 'other' antimicrobial group increased in all provinces from 2001 to 2010 with the exception of Prince Edward Island, although by varying amounts (10% to 61% increases).

DISCUSSION

The overall use of antimicrobials in Canada has dropped from 1995 to 2010, and the tetracycline and sulfonamide-trimethoprim groups have contributed to this decline. The use of the 'other' antimicrobials has increased, however. These results may suggest that switches are being made among these groups, particularly among the antimicrobials used to treat urinary tract infections.