The Use of Fluoroquinolones in Animal
Health
Introduction
Animals, like people, may suffer from bacterial
infections which may need to be treated with antimicrobial medicines. The
veterinary surgeon will examine the animal, make a diagnosis and prescribe
the most appropriate antimicrobial from the range available. The most
appropriate medication may be from a class of antimicrobials called the
fluoroquinolones.
What are fluoroquinolones?
Fluoroquinolones are a modern group of synthetic
therapeutic antimicrobials, active against a range of bacteria.
In common with other therapeutic antimicrobials used to
treat bacterial infection in animals, there are related antimicrobials used
in human medicine. This is inevitable because frequently similar bacteria
can cause disease in man and animals. Consequently the antimicrobials used
to treat the infection are similar.
All therapeutic antimicrobials are categorised as
Prescription Only Medicines. The initials POM-V show that it is a Veterinary
Prescription Only Medicine. These are available only on prescription from a
veterinary surgeon. Product labels and knowledge of the disease, together
with specific guidelines, direct veterinary surgeons toward prudent use of
antimicrobials.
Marketing Authorisation
Therapeutic antimicrobials must pass strict examination
by the Veterinary Medicines Directorate and fulfil criteria of safety,
quality and efficacy before being given a Marketing Authorisation.
'Safety' includes safety to the treated animal, the user,
the environment and, for food animals, the consumer. ‘Quality’ confirms that
what is on the label is in the bottle and ‘Efficacy’ confirms that it has
been shown to effectively treat the diseases for which the product is
indicated.
Products used to treat infections in farm livestock have
a withdrawal period. This is the additional time (which may be zero) 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 sometimes
necessary to treat the sick as well as the in-contact birds, some of which
will be incubating the disease (i.e. all the birds in the one house).
Fluoroquinolones are sometimes 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 adversely affect
public health. At the core of the debate is the fact that treatment of
infections with antimicrobials can lead to the development of bacterial
resistance. It is suggested that, if resistant bacteria are passed from
animals to humans through the food chain, then reduction in the clinical
efficacy of a human antimicrobial may 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
using these products to treat animal diseases. Subsequent meetings have
resulted in various recommendations to further reduce the possible
development of bacterial 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
animal 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 pose a threat to animal health and
welfare and 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 health plans include Standard Operating
Procedures (SOPs) for hygiene and vaccination programmes. Good animal
husbandry is used to reduce the occurrence of disease and the need to use
therapeutic antimicrobials.
2. Fluoroquinolones should be used where the prescribing
veterinary surgeon believes that fluoroquinolones are the most appropriate
antimicrobial for an infection specified in the UK Marketing Authorisation
and in accordance with current UK and EU legislation:
(i) Fluoroquinolones can only be administered under
prescription by a veterinary surgeon: they are classified POM-V
(Prescription Only Medicine - Veterinary)
(ii) They are for therapeutic use only, based on the
professional experience of the individual case or farm and, ideally,
following susceptibility testing of the causative bacteria to determine
the most suitable treatment. When used in anticipation of emergency
diseases outbreaks where there is no time to conduct sensitivity testing
of target pathogens (e.g. 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 in
the EU is collaborating with national authorities on the development and
interpretation of monitoring programmes designed to identify meaningful
changes in the susceptibility 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.
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Reviewed June 2010 |
