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CONSUMER ATTITUDES

The Use of Fluoroquinolones in Animal Health

Introduction

Animals, like humans, suffer from bacterial infections which may need to be treated with antimicrobial drugs. These must always be prescribed by a veterinary surgeon who has the choice of several groups of antimicrobials, including the fluoroquinolones.

What are fluoroquinolones?

Fluoroquinolones are a modern group of synthetic therapeutic antimicrobials, active against a range of bacteria.

With most therapeutic antimicrobials used to treat bacterial infection in animals there are related antimicrobials used in human medicine from the same family. This is also true for the fluoroquinolones, which is inevitable because frequently similar bacteria cause disease in humans and animals and so have to be treated with similar antimicrobials.

All therapeutic antimicrobials are categorised as Prescription Only Medicines - Veterinary (POM-V) and so are available only on prescription from a veterinary surgeon. Labelling directs veterinary surgeons toward prudent use.

Marketing Authorisation

Therapeutic antimicrobials must pass strict examination by the Veterinary Medicines Directorate and fulfil criteria of safety, quality and efficacy before being allowed a Marketing Authorisation for use in animal health. 'Safety' includes safety to the treated animal, the user, the environment and, for farm animals, the consumer.

In products used for farm livestock, a withdrawal period is calculated i.e. the time that must follow after the last treatment before the animal, or its produce, can be used for human consumption.

(For more details on what is needed to get a marketing authorisation, see NOAH briefing document 19 ‘Controls on animal medicines’)

How are fluoroquinolones given?

Around half a dozen fluoroquinolones have marketing authorisations in the UK, for use in one or more of the following species; cattle, pigs, chickens, turkeys, dogs, cats and other pet animals.

When dogs and cats need antimicrobials, the veterinary surgeon treats an individual animal. A combination of fluoroquinolone injections and tablets may be used. Other pet animals may have medicines administered orally in water or milk. Cattle and pigs are treated on an individual basis with oral or injectable products.

When chickens or turkeys become ill, it is necessary to treat all in-contact birds i.e. all the birds in the one shed. Some birds will be showing clinical signs whereas some, although they may appear clinically normal, may be incubating the disease. Fluoroquinolones are given in the drinking water for a short period of time under the direction of the prescribing veterinary surgeon.

Why is there concern about their use in animals?

For some time now, scientists have been debating whether the use of antimicrobials in veterinary medicine might have an adverse impact on public health. At the core of the debate is the fact that treatment of animals with antimicrobials can lead to the development of bacterial resistance, as also can occur following human therapy. It is postulated that, if these bacteria are passed from animals to humans through the food chain, then reduction in the clinical efficacy of an antimicrobial could be possible. However, a World Health Organisation meeting in 1998, while stressing the need for care in the use of fluoroquinolones, did not find any clear evidence of harm to man from the use of these products in animals. Subsequent meetings have resulted in various recommendations to further contain possible development of resistance.

Nevertheless, in the United States, the Food and Drug Administration (FDA) have withdrawn the use of fluoroquinolones in poultry. The scientific basis for this action has been challenged by various institutions representing the poultry veterinarians and the manufacturer. They are convinced, as are many scientists and officials, that the responsible use of fluoroquinolones for the therapy of life-threatening poultry diseases does not result in a danger to public health. In Europe (2001) the European Medicines Evaluation Agency gave the opinion that reducing therapeutic medicines available to the veterinary surgeon can result in animal health problems which ultimately can also be considered a threat to human health.

Industry guidance for fluoroquinolone use

Fluoroquinolone antimicrobials are recognised as making an important contribution to the treatment of disease in both human and animal patients. The UK animal medicine industry re-emphasises the following principles which guide their responsible marketing and give advice for use of this important group of antimicrobials.

1. Farm hygiene and management programmes such as vaccination, appropriate animal husbandry and care should be used, as relevant, to reduce disease and the need for therapeutic intervention.

2. Fluoroquinolones should only be used where the prescribing veterinary surgeon believes that fluoroquinolones are the most appropriate antimicrobial for an indication specified in the UK Marketing Authorisation and in accordance with current UK and EU legislation:

(i) Fluoroquinolones can only be given under prescription by a veterinary surgeon: they are classified POM-V (Prescription Only Medicine - Veterinary).

(ii) They are for therapeutic use only, on the basis of professional experience of the individual case or farm and, where clinical circumstances allow, following sensitivity testing to determine the most suitable treatment. In anticipation of emergency disease outbreaks where there is no time to conduct sensitivity testing of target pathogens (eg E Coli), regular susceptibility monitoring is carried out.

3. Advertising must comply with the requirements of the NOAH Code of Practice for the Promotion of Animal Medicines and current UK legislation.

Monitoring sensitivity

The animal medicine industry in the UK and elsewhere is collaborating with national authorities on the development and interpretation of monitoring programmes designed to identify meaningful changes in the sensitivity of human and animal pathogens to fluoroquinolones (and other compounds). We will continue to work with the veterinary and medical professions to develop the data necessary to enable scientifically valid decisions to be taken on the appropriate selection and use of antimicrobials in humans and animals.

Reviewed October 2007