-M.A. Payne et
al. JAVMA 215:28-32, 1999.
1-As seen in Wool
& Wattles, the AASRP Newsletter, Vol. 27, #2, April-June, 1999.
2-The Ohio State
University Extension Veterinary Medicine News Letter Volume 26, No. 1,
1999
3-http://extension.usu.edu/files/agpubs/drugs.htm
-Abstracted from JAVMA, Vol 215: pg 28-31 (No. 1, July 1, 1999)
DRUGS PROHIBITED FROM EXTRALABEL USE IN FOOD ANIMALS
NOTE:
The current list of prohibited drugs includes furazolidone and nitrofurazone,
but it contains the parenthetical statement (except for approved topical
use). FDA plans to remove this parenthetical statement. Once
this prohibition is in place, the revised list will state that the following
drugs (both animal and human), families of drugs, and substances are prohibited
for extra-label uses in all food-producing animals.
(1) Chloramphenicol;
(2) Clenbuterol;
(3) Diethylstilbestrol
(DES);
(4) Dimetridazole;
(5) Ipronidazole;
(6) Other
nitroimidazoles;
(7) Furazolidone,
Nitrofurazone, other nitrofurans;
(8) Sulfonamide
drugs in lactating dairy cattle (except approved use of sulfadimethoxine,
sulfabromomethazine, and sulfaethoxypyridazine);
(9)
Fluoroquinolones; and
(10) Glycopeptides.
Under the Animal Medicinal Drug Use Clarification Act of 1994 (AMDUCA), the FDA has the power to prohibit the use of certain drugs in food animals. Currently it is ILLEGAL to prescribe or use 8 drugs or drug classes in food animals. Extralabel use of any of these drugs is ILLEGAL and represents one of the FDA's highest regulatory priorities.
Prohibited Drugs:
Diethylstilbestrol
(DES) - was
banned in 1979 because of carcinogenic potential and is no longer available.
Chloramphenicol
- can cause a rare idiosyncratic aplastic anemia in people;
the use of all preparations, including ophthalmic ointments in food animals
is forbidden. The newer florfenicol product (Nuflor®) is thought
to lack the group associated with aplastic anemia and may be used in an
extralabel fashion.
Fluoroquinolones
- Although data have not been sufficiently conclusive to prevent approval
of sarafloxacin for chickens and beef cattle, it prompted FDA-CVM to prohibit
extralabel use of these compounds in 1997. Fluoroquinolone
products labeled for either humans or companion animals may not be used
in food animals. Any deviation from a food animal label (such as use with
a different species, dosage, route of administration, or disease indication)
is similarly illegal. In the case of the approved beef cattle formulation
of enrofloxacin (Baytril 100), this prohibition extends to
all nonbeef-production animals, including lactating and nonlactating dairy
cows, heifer replacements, and veal calves (and sheep, goats, and deer).
Enrofloxacin may not be stored in dairy farm drug cabinets.
Dipyrone
- Because products are not available for either humans or animals, dipyrone
is not typically included on lists of extralabel prohibitions published
by FDA-CVM. Old stockpiles of the drug, however, do occasionally surface.
Any use of dipyrone in food animals remains a violation of the Food Drug
and Cosmetic Act. Dipyrone
was used as an antipyretic, anti-inflammatory, and analgesic
but has serious toxic effects in people. The FDA removed approval
for human products in 1977 and required that marketing for companion animals
cease in 1995 in order to stop use in food animals. If old stockpiles
of the drug surface, their use is illegal.
Nitroimidazoles
- including dimetridazole, metronidazole, and ipromidazole have documented
carcinogenicity. Although used in humans and companion animals, the use
of any member of this drug class in food animals is illegal. Use
of any Sulfonamide other than sulfadimethoxine in dairy cattle older than
20 months (regardless of lactation status) is illegal. Use of sulfadimexthine
in dairy cattle in a higher than labeled dose or in the sustained release
form is illegal. The article does not mention possible implications
for dairy sheep and dairy goats.
Nitrofurans
- have also been banned because of carcinogenicity and mutagenicity.
Approval of human systemic preparations was withdrawn in 1974 and of systemic
animal nitrofuran products in 1991. Studies have recently documented
that topicals labeled for treatment of pinkeye in cattle, sheep, and goats
and surface wounds in all livestock result in milk and meat residues.
Manufacturers have agreed to remove their food animal indications.
Topical Nitrofurans Are Now Prohibited
- FDA is issuing an order prohibiting the extralabel use of topical
nitrofuran animal and human drugs in food-producing animals. This
order is based on evidence that extralabel use of topical nitrofuran drugs
in food-producing animals may result in the presence of residues that are
carcinogenic and have not been shown to be safe. A carbon-14 (C-14) radio-label
residue depletion study conducted by the FDA showed that detectable levels
of nitrofuran derivatives are present in edible tissues (milk, meat, kidney,
liver) of cattle treated by the ocular (eye) route. The study indicates
that use of these nitrofuran products may pose a risk to public health
because residues of known carcinogens are present in edible tissues.
Sulfonamide
- use in dairy cattle - Only 1 of the 3 sulfonamides that have label indications
for lactating cows, sulfadimethoxine (SDM), is currently being marketed.
Currently, use of any sulfonamide other than SDM in dairy cattle older
than 20 months is illegal. Additionally, extralabel use of SDM in lactating
dairy cattle is prohibited (for example, use of a higher dose or slow-release
SDM boluses in dairy cattle is not permitted).
Clenbuterol
- has been approved in foreign countries as a bronchodilator in horses
or as a uterine relaxant in cattle and sheep. It has been used illegally
in food animals to increase weight gain and lean body mass and has resulted
in more than 1,000 emergency hospitalizations and several deaths of people
in Europe. Now that Ventipulmin® Syrup is approved for heaves in horses,
the FDA will monitor for illegal food animal residues and unusual sales
patterns of the drug. Two veterinarians have already been convicted
on charges of conspiring to smuggle clenbuterol into the US from Canada.
Glycopeptides
- The only glycopeptide antibiotic available in the United States is the
human product vancomycin (Vancocin).
Vancomycin is often the treatment of last resort for methicillin-resistant
Staphylococcus aureus (MRSA) infections in humans. Avoparcin, a compound
chemically similar to vancomycin, has been used in European animal feeds
as a growth promoter since the mid-1970s. FDA-CVM in 1997 issued an order
prohibiting the extralabel use of all glycopeptides in food animals. The
restriction of fluoroquinolone and glycopeptide use represents a novel
exercise of FDA-CVM discretionary authority: restriction based not on the
drug’s direct toxicity, but on its potential for increasing human pathogen
resistance.
Extralabel use of medicated feed
- Section 530.11 of AMDUCA specifically prohibits the “extralabel use of
an approved new animal drug or human drug in or on an animal feed.” As
a matter of enforcement discretion, FDA-CVM generally has not objected
to mixing a drug with an individual animal’s feed, but extralabel mass
medication in feed is prohibited “without limitation or exception.” This
prohibition extends to all drugs; not just those discussed in this article.
Nonsteroidal
anti-inflammatory drugs - prohibited as well Phenylbutazone,
known as "bute," is a veterinary drug only label-approved by the
Food & Drug Administration for use by veterinarians in dogs and horses.
It has been associated with debilitating conditions in humans and it is
absolutely not permitted for use in food-producing animals. USDA/FSIS
has conducted a special project to for this drug in selected bovine slaughter
plants under federal inspection. An earlier pilot project by FSIS found
traces less than 3% of the livestock selected for testing, sufficient cause
for this special project. There is no tolerance for this drug in food-producing
livestock, and they and their by-products are condemned when it is detected.
Dairy producers must not use this drug in food-producing livestock and
if it is found, those producers will be subject to FDA investigation and
possible prosecution.
Other
dairy prohibitions - With the exception of SDM, none of the drugs or
drug classes listed may be legally labeled for dairy cattle and, if found
during an inspection, would trigger regulatory action. In addition to dipyrone,
there are two drugs that are not currently on the AMDUCA prohibited list
but which result in “debits” if found during a dairy inspection. These
are dimethyl sulfoxide and collodial silver. The use of ionophore compounds
(i.e., monensin, lasalocid) in lactating dairy cattle rations is prohibited.
State
of aminoglycosides - A number of veterinary organizations have established
or support policies that discourage the extralabel use of aminoglycosides.
These position statements are nonbinding and should not be confused with
the legal prohibitions described. Extralabel use of Aminoglycosides
has been discouraged by organizations such as AABP and AVMA, but these
position statements are nonbinding and should not be confused with legal
prohibitions.
Treatment
of companion animals - The prohibitions described in this article pertain
to food-producing animals only and not companion species, such as dogs
and cats.
Medicated
Feed - Extralabel use of any drug in or on an animal feed is
also forbidden by AMDUCA, but as a matter of enforcement discretion, FDA-CVM
has generally not objected to mixing a drug with an individual animal's
feed. Extralabel mass medication of any drug in feed is prohibited without
exception.
-M.A. Payne et
al. JAVMA 215:28-32, 1999.
1-As seen in Wool
& Wattles, the AASRP Newsletter, Vol. 27, #2, April-June, 1999.
2-The Ohio State
University Extension Veterinary Medicine News Letter Volume 26, No. 1,
1999
http://prevmed.vet.ohio-state.edu/extension/newsletterv26no1.htm
3-http://extension.usu.edu/files/agpubs/drugs.htm
-Abstracted from JAVMA, Vol 215: pg 28-31 (No. 1, July 1, 1999)
Aminoglycoside use in cattle receives additional voluntary ban
A resolution to ban the use of aminoglycosides in cattle was passed by the American Veterinary Medical Association (AVMA) House of Delegates in July 1998. The AVMA has now joined the American Association of Bovine Practitioners, the Society for Theriogenology, and the state veterinary medical associations from Wisconsin, Iowa, Kansas, and Michigan. The resolution supports a voluntary ban on the extra-label use of aminoglycoside antibiotics, particularly gentamycin in cattle. The ban is to remain in effect until further scientific information becomes available.
The concern relates to the understanding
that systemic use of aminoglycosides present a potential conflict to standards
of practice because the scientific justification is limited. Residues can
be found in renal tissue for an undetermined, extended period of time.
In order to comply with AMDUCA regulations, extra-label drug use must include
a sufficiently extended withdrawal period so that no residues are found
in meat of milk products. Dairy producers using aminoglycosides and veterinarians
prescribing the use of aminoglycosides will be in indefensible positions
should residues be found.