Section 1 | Resistance, Stewardship, & Categories of Antimicrobials

Categorization of Antimicrobial Drugs

Understanding Antimicrobials

Governments around the world have recognized the growing threat that antimicrobial resistance (AMR) has on our ability to treat infections in humans.

Why is this so important for animal health? Many of the same antimicrobials used to treat and prevent infections in human medicine are also used in animals.

Some antimicrobials are more important than others for treating people. Health Canada classifies them into four categories, based on whether:

1. The antimicrobial is a preferred option for treating serious infections in humans
2. The antimicrobial is a ‘last resort’ drug with few or no alternative treatment options available

Table 1. Health Canada Categories for Antimicrobials

While AMR is a concern for all drug products, we are most concerned with preventing resistance to medically important antimicrobials (Category I, II, and III antimicrobials).