SALES OF ANTIMICROBIAL PRODUCTS USED AS VETERINARY MEDICINES OR GROWTH
PROMOTERS IN THE UK FROM 1993-1998
Summary
This paper reports for the first time data for sales of veterinary
antimicrobial products in the UK. It shows there was a significant rise in the sale of
antimicrobials from 1993-1996, followed by a fall in 1997 and 1998 to pre-1994 levels.
Over the period 1993-1998 inclusive antimicrobials sales in food animals accounted for 95%
(555 tonnes) of the mean annual sales of 584 tonnes. Just under half (47%) of the total
sales of antimicrobials for use in food animals is accounted for by tetracyclines whereas
fluoroquinolones account for only about 1 tonne (0.2%).
Between 83%-90% of the antimicrobials sold for use in food animals
during the 6-year period were for therapeutic purposes, with growth promoters accounting
for 10-17%. About 80% of antimicrobial products are administered via feedstuffs and most
is used for pigs and poultry but further work is needed to determine the species breakdown
more accurately.
The VMD will continue to collect and publish information on
antimicrobial sales on an annual basis and seek to refine the data as more information
becomes available. As results of antimicrobial resistance surveillance become available,
it will be possible to compare trends in the sales of antimicrobials with patterns of
resistance. The figures also provide a baseline for consideration of the Government's
policy to seek to reduce the overall use of antimicrobials in order to maintain
antimicrobial efficacy.
Introduction
The emergence of antimicrobial resistance as a serious problem in human
medicine has led to increasing concerns about the use of antimicrobial products in
medicine, veterinary medicine, animal production, agriculture and horticulture. These
concerns have been set out in recent national and international reports, including those
from the House of Lords Committee, the Advisory Committee on the Microbiological Safety of
Food, the European Union's Committee for Veterinary Medicinal Products and the Council of
Ministers, and the World Health Organisation.
In the UK, the Government has made clear that it takes the problem of
antimicrobial resistance very seriously and a comprehensive strategy is being developed to
address the issue in order to maintain the effectiveness of antimicrobial products. A key
element of this plan is the collection of information on the amounts of antimicrobial
products used in veterinary medicine and animal production in the UK. This information
would assist the regulatory authority to monitor changes in the overall use of
antimicrobial products, relate these to changes in antimicrobial resistance and identify
where reviews of prescribing practices might be appropriate.
The Veterinary Medicines Directorate (VMD), an executive agency in the
Ministry of Agriculture, Fisheries and Food which is responsible for the authorisation of
veterinary medicines in the UK, has collected sales figures of antimicrobials authorised
as veterinary medicinal products, growth promoters or coccidiostats (the last two are
authorised under separate arrangements by the EU as feed additives) for the period
1993-1998. The information was provided by the veterinary pharmaceutical companies
marketing these products in the UK. This paper summarises the information that has been
provided.
Total Sales
Table 1 shows the amounts of therapeutic antimicrobials and
antimicrobial growth promoters sold for use in food animals (including aquaculture) from
1993-1998 expressed as tonnes of base active ingredients. The table also includes the
total sales of therapeutic antimicrobials sold for use in non-food animals (horses, dogs,
cats etc.) and the total amounts of antimicrobials sold for use in food animals and
non-food animals during this period.
Table 1 : Sales of antimicrobial therapeutic products and growth
promoters (tonnes active ingredient) 1993-1998
| |
1993 |
1994 |
1995 |
1996 |
1997 |
1998 |
Therapeutic antimicrobials
- food animals |
392 |
445 |
486 |
533 |
495 |
433 |
Annual increase/decrease |
|
14% |
9% |
10% |
-7% |
-13% |
Antimicrobial growth
promoters |
83 |
88 |
122 |
96 |
69 |
89 |
Annual increase/decrease |
|
6% |
39% |
-21% |
-28% |
29% |
Total antimicrobials - food
animals |
475 |
533 |
608 |
629 |
564 |
522 |
Annual increase/decrease |
|
12% |
14% |
3% |
-10% |
-7% |
| Therapeutic antimicrobials - non-food animals* |
20 |
24 |
32 |
30 |
32 |
32 |
Annual increase/decrease |
|
20% |
33% |
-6% |
7% |
0% |
Total antimicrobials - food
animals and non-food animals |
495 |
557 |
640 |
659 |
596 |
554 |
Annual increase/decrease |
|
13% |
15% |
3% |
-10% |
-7% |
* horses, dogs, cats etc.
Therapeutic and total antimicrobial sales in food animals reached a
peak in 1996 and then fell by 1998 to just below the levels sold in 1994. The amounts of
antimicrobial growth promoters peaked a year earlier, then fell sharply in 1997 after the
withdrawal of avoparcin before rising again in 1998. Between 83-90% of the antimicrobials
sold for use in food animals during the 6-year period were for therapeutic purposes, with
growth promoters accounting for 10-17%. In non-food animals the amounts sold increased to
1995 and remained similar thereafter.
Sales by antimicrobial group
Table 2 shows the sales of various groups of antimicrobials in food
animals from 1993-1998.
Table 2 : Sales of therapeutic antimicrobials (tonnes active
ingredient) for use in food animals 1993-1998
| |
1993 |
1994 |
1995 |
1996 |
1997 |
1998 |
Tetracyclines |
231 |
250 |
255 |
300 |
283 |
233 |
Trimethoprim/sulphonamides |
87 |
110 |
119 |
125 |
93 |
80 |
ß lactams |
54 |
56 |
59 |
63 |
62 |
60 |
Aminoglycosides |
12 |
16 |
36 |
25 |
21 |
24 |
Macrolides |
<1 |
3 |
5 |
6 |
18 |
24 |
Fluoroquinolones |
<1 |
1 |
1 |
1 |
2 |
1 |
Others* |
8 |
9 |
11 |
13 |
16 |
11 |
Total |
392 |
445 |
486 |
533 |
495 |
433 |
* Includes lincosamides, tiamulin, oxolinic acid, novobiocin,
thiostreptan
Tetracyclines, trimethoprim/sulphonamides and ß-lactams (including
penicillin) together accounted for 72-81% of therapeutic antimicrobials sold for use in
food animals, with tetracycline sales accounting for 42-50%. Most of the tetracyclines are
used in pigs and poultry in medicated feedingstuffs (MFS) to treat various disorders
including respiratory disease. Large quantities of tetracyclines were used during the
1990s as a result of the introduction of Porcine Reproductive and Respiratory Syndrome
(PRRS) to the UK. Better understanding and management of this disease and the introduction
of vaccines to prevent respiratory diseases in pigs are likely to have contributed to the
decline in tetracycline sales.
Sales of macrolides (e.g. tylosin) and aminoglycosides (e.g.
streptomycin and neomycin) increased during the period but fluoroquinolone sales have
remained at around 1 tonne of active ingredient since they were first authorised in 1993.
The figures reported do not take into account the relative potencies of the different
active ingredients. Further information would be needed to address this issue.
Table 3 summarises the sales of coccidiostats for 1993-1998. They are
not related to any antibiotic used in human therapy. Coccidiostats are used exclusively in
animals to prevent coccidiosis, particularly in poultry. Sales peaked in 1994 and have
fallen since then except in 1997.
Table 3 : Sales of coccidiostats (tonnes active ingredient) in the
UK 1993-1998
|
1993 |
1994 |
1995 |
1996 |
1997 |
1998 |
Coccidiostats |
114 |
139 |
124 |
113 |
121 |
103 |
Annual increase/decrease |
|
22% |
-11% |
-9% |
7% |
-15% |
Sales by route of administration
Table 4 lists the major types of formulation of antimicrobials sold
during 1993-1998. Total sales increased during the period, reaching an overall peak in
1996 before falling in the subsequent two years. This was mainly due to medicated
feedstuffs which accounted for 81-84% of products sold.
Table 4 : Sales of therapeutic antimicrobials (tonnes active
ingredient) by route of administration in food animals 1993-1998
| |
1993 |
1994 |
1995 |
1996 |
1997 |
1998 |
Medicated feedstuffs |
328 |
361 |
393 |
433 |
405 |
362 |
Injectable |
37 |
40 |
45 |
43 |
30 |
24 |
Water/Oral |
18 |
34 |
37 |
47 |
51 |
38 |
Intramammaries |
5 |
5 |
7 |
6 |
6 |
7 |
Other * |
|
5 |
4 |
4 |
3 |
2 |
Total |
392 |
445 |
486 |
533 |
495 |
433 |
* includes aerosols, creams, ear and eye medications
Sales by food animal species
Sales of antimicrobials for use in different species of food animals
are shown in Table 5. It is clear from this table that 68-72% of antimicrobial products
are authorised for use in more than one species.
It is likely that most are used in pigs and poultry but it is currently
impossible to determine the exact usage in different species. An independent study is
currently being commissioned to provide further data on this aspect of the use of
antimicrobials in food animals.
Table 5 also shows considerable decline in the sales of antimicrobials
used in the aquaculture industry between 1993-1998 at a time when fish production was on
the increase (see Table 6). In 1993 the sale of one tonne of antimicrobial active
ingredient produced 5,500 tones of salmon and trout, by 1998 the same amount of
antimicrobials was producing 25,200 tonnes of fish (four fold increase). The reduction in
the sales of antimicrobials in aquaculture is due mainly to better husbandry practices and
the introduction of specific fish vaccines.
Table 5 : Sales of therapeutic antimicrobials (tonnes
active ingredient) by species 1993-98
Species |
1993 |
1994 |
1995 |
1996 |
1997 |
1998 |
Cattle |
10 |
12 |
14 |
11 |
9 |
11 |
Sheep |
<1 |
<1 |
<1 |
<1 |
<1 |
<1 |
Pigs |
89 |
91 |
109 |
117 |
121 |
90 |
Poultry |
10 |
16 |
17 |
20 |
17 |
14 |
Fish (salmon and trout ) |
10 |
7 |
7 |
7 |
9 |
5 |
Multi-Species* |
273 |
319 |
339 |
378 |
339 |
313 |
Totals** |
392 |
445 |
486 |
533 |
495 |
433 |
* a combination of two or more of the following species- cattle, pigs,
sheep and poultry
** does not include growth promoters all of which are multi-species
Antimicrobials sales and livestock reared
Table 6 shows the relationship between the live weights of animals
slaughtered and the volumes of antimicrobials sold during 1993-1998. The table shows an
increase in the total live weight of livestock slaughtered between 1993-1995 which
corresponds to the trend in sales of antimicrobials during this period. The total live
weight of livestock slaughtered declined in 1996, mainly due to the sharp decline in
cattle slaughterings as a result of the BSE crisis but increased in the subsequent two
years. Antimicrobial sales, on the other hand, reached a peak in 1996 before falling in
the following two years. The fall in sales of antimicrobials in 1997 and 1998 occurred at
a time when the total live weight of livestock slaughtered increased.
Table 6 : Live weight (‘000 tonnes) of animals slaughtered*
against antimicrobials (tonnes active ingredient) sales 1993-1998
*Source- Agriculture in the United Kingdom 1993-1998. Ministry of Agriculture and Food.
VETERINARY MEDICINES DIRECTORATE
APRIL 2000
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