Q&As
Approval of Baytril 100

What is Baytril?

Baytril is the brand name for a veterinary drug, enrofloxacin, of the antibiotic class of fluoroquinolones. Health Canada recently approved Baytril 100 (a specific dose of Baytril - 100 mg/mL injectable solution) for therapeutic use against bacterial respiratory disease in beef cattle. Before Baytril 100 was approved for use as a veterinary drug, a comprehensive scientific review was undertaken to assess the drug's safety, efficacy and quality. Before approval of Baytril 100, no fluoroquinolones were approved in Canada for use in food-producing animals, however, Baytril has been approved for sale in Canada for use in dogs and cats for many years.

Why is this drug needed?

Baytril 100 will provide veterinarians with an alternative course of treatment for bovine respiratory disease only when other available drugs are not effective.

If fluoroquinolones are used in human medicine, with growing concerns about antimicrobial resistance (AMR), why would they be used in animals?

It is anticipated that the use of Baytril 100 in beef cattle will be very limited. Baytril 100 is a prescription only drug, and the warning statements on the label stipulate the conditions in which it should be used. This drug should not be used in an extra-label manner, i.e., a manner that is not consistent with what is indicated on the label, package insert or product monograph. Baytril 100 will be used for treating individual relapse cases of bovine respiratory disease after initial treatments have failed.

Before Baytril 100 was approved as a veterinary drug for use in beef cattle, a comprehensive scientific evaluation of its manufacturing procedures, clinical efficacy and safety in the intended species, toxicology, microbiological safety and antimicrobial resistance considerations were undertaken. Post-market surveillance is important in monitoring the safety of any drug, especially in the case of antimicrobials with regards to AMR. Health Canada, through the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS), will monitor and track any increases in antimicrobial resistance in E. coli and Salmonella spp. from beef cattle. CIPARS will collect representative bacterial samples from abattoir-level, retail beef-level and from human tissue samples. Health Canada's Veterinary Drugs Directorate (VDD) will also track and assess any Adverse Drug Reactions (ADR) reports submitted by veterinarians and manufacturers.

Should there be an apparent risk of increasing resistance to this drug as a result of usage in beef cattle, Health Canada will ensure that appropriate interventions will be taken which could, if necessary, lead to withdrawal of the product from the market.

What are the safeguards?

Veterinary drugs for food-producing animals that are reviewed by Health Canada undergo three streams of scientific evaluation encompassing reviews of data on manufacturing and chemistry, efficacy and safety in the intended species, and human safety. In the case of manufacturing and chemistry, the data must demonstrate that the drug is composed of quality ingredients and will be manufactured according to stringent standards. From an animal health perspective, data must demonstrate that the drug is effective and safe for the animal. In the case of human safety, data must address issues relating to toxicity, microbiology (including antimicrobial resistance) and demonstrate that residues of the drug in edible tissue have undergone thorough examination and that this application of the drug would not pose any undue risks to consumers eating the food derived from the treated animal. Health Canada also ensures that the product is labelled to meet the prescribed standards in the regulations so that the product can be used safely.

In the case of Baytril 100, Health Canada requires the manufacturer to include explicit directions on the label: available only by prescription through a veterinarian; no extra-label use permitted; specific withdrawal period (36 days); not to be used in veal calves; dairy cattle or any other
food-producing species. The label also stipulates measures to limit the potential development of antimicrobial resistance such that Baytril 100 should only be used when other antimicrobials are not effective.

In addition, CIPARS will be monitoring post-market changes in antimicrobial resistance levels linked to the use of this drug. This will provide VDD with the data required to assess the continued safety of Baytril 100 after its approval. Appropriate risk management decisions will be taken if the surveillance data show that there is an unacceptable risk to human health as a result of continued use of this drug in beef cattle.

How many Health Canada scientists reviewed data submitted for Baytril and what are their qualifications?

Data submitted for Baytril was reviewed by a team of 12 Health Canada scientists in three different review Divisions of the Veterinary Drugs Directorate. Their qualifications are:
Human Safety Division: 4 PhDs; 1 veterinarian and 1 MSc;
Clinical Evaluation Division: 4 veterinarians (two of these scientists also hold a MSc in Epidemiology and a MSc and PhD in Pharmacology); and
Manufacturing and Chemical Evaluation Division: 1 BSc and 1 PhD in Chemistry.

Is Baytril used in other countries?

Baytril is approved for sale in 25 countries, including member states of the European Union (EU) and the United States (US) for use in beef cattle. It is also approved for use in beef cattle in New Zealand and Finland under stringent conditions similar to Canada. Over the last few years, the Food and Drug Administration (FDA) has held public hearings on the safety of enrofloxacin for use in poultry following the Center for Veterinary Medicine's proposal to withdraw approval for the use of this product in drinking water for poultry. Public health concerns raised in the US have focussed on the use of Baytril in poultry production and not on its use in beef cattle.

If the US is currently reviewing the safety of enrofloxacin for use in poultry, why is Health Canada approving it at this time?

There are important differences in how this drug is used in various animal species which have an impact on food safety. That is why the US is reviewing use of Baytril in poultry, but not use in beef cattle. In Canada, Baytril is not approved for use in poultry.

How can Health Canada be sure that the drug will not be misused?

When Health Canada approves a veterinary drug for sale in Canada, it requires the manufacturer to provide specific instructions on the label for direction to veterinarians prescribing the drug. When used in accordance with the directions on the label, the food derived from treated animals is considered safe for human consumption.

The Canadian Food Inspection Agency (CFIA) has a program in place to monitor Canada's food supply and has methods of detecting violative residues of a drug (including Baytril) in edible tissues derived from animals.

What about the impact on the environment?

An environmental impact assessment of this application was completed, and the data demonstrated that the drug binds tightly with soil and manure, that is, its bioavailability is very low. Given this and its limited use, there is very low risk of adverse environmental impact from the use of Baytril 100 in beef cattle.

What about the implications of antimicrobial resistance?

Over a period of two years, an exhaustive assessment was conducted by Health Canada's scientists. International studies on antimicrobial resistance issues related to this drug were considered as part of this assessment. Analysis of available scientific studies, including research and surveillance data, indicates that there is no apparent risk of antimicrobial resistance when Baytril 100 is used prudently in beef cattle for therapeutic purposes. Health Canada's evaluation concluded that the use of Baytril 100 in beef cattle in Canada, as directed on the label, will not pose undue human health risk associated with antimicrobial resistance in food-borne bacterial pathogens such as Escherichia coli, Campylobacter spp. and Salmonella spp.