WORLD HEALTH ORGANIZATION FOOD AND AGRICULTURE
ORGANIZATION
ORGANISATION MONDIALE DE LA SANTE ORGANISATION POUR L'ALIMENTATION
ET L'AGRICULTURE
VBC/PDS/84.57
ORIGINAL: ENGLISH
DATA SHEET ON PESTICIDES No. 57
BRODIFACOUM
CLASSIFICATION:
Primary use: Rodenticide
Chemical group: Bromylated Coumarin compound
(Organobromine)
It must be noted that the issue of a Data Sheet for a
particular pesticide does not imply endorsement of the pesticide by
WHO or FAO for any particular use, or exclude its use for other
purposes not stated. While the information provided is believed to
be accurate according to data available at the time when the sheet
was compiled, neither WHO nor FAO are responsible for any errors or
omissions, or any consequences therefrom.
The issue of this document does Ce document ne constitue pas une
not constitute formal publication. Il ne doit faire
publication. It should not be l'objet d'aucun compte rendu ou
reviewed, abstracted or quoted résumé ni d'aucune citation sans
without the agreement of the l'autorisation de l'Organisation
Food and Agriculture des Nations Unies pour
Organization of the United l'Alimentation et l'Agriculture
Nations or of the World Health ou de l'Organisation Mondiale de
Organization. la Santé.
1. GENERAL INFORMATION
1.1 COMMON NAME: Brodifacoum (ISO, BSI)
1.1.1 Identity:
IUPAC and CAS No. 1: 3-(3-(4'-bromobiphenyl-4-yl)-1,2,3,4-
tetrahydro-1-naphthyl)-4-hydroxycoumarin
CAS No. 1: 3-(3-(4'-bromo(1,1'-biphenyl)-4-yl)-1,2,3,4-
tetrahydro-1-naphthalenyl)-4-hydroxy-2H-1-benzopyran-2-one
CAS Reg. No.: 56073-10-0
Molecular formula: C31H23BrO3
Molecular weight: 523.4
Structural formula: 
1.1.2 Synonyms: Brodifacoum; PP 581(R); Ratak(R); Volak (R);
WBA 8119
1.2 SYNOPSIS: Brodifacoum is a bromylated hydroxycoumarin derivative;
an indirect anti-coagulant; and an effective stomach poison
which inhibits prothombin formation and induces capillary damage.
To be effective it usually requires only a single ingestion of a
bait formation in one feeding to produce a kill. It is extremely
toxic to a broad spectrum of rodents and other small mammals but
due to its low bait concentration and its delayed effect it is
considered to be only of low acute toxicity hazard to humans.
1.3 SELECTED PROPERTIES
1.3.1 Physical characteristics - Brodifacoum is an off-white to fawn
coloured, odourless powder melting at 228-232'C.
1.3.2 Solubility - It is of very low solubility in water; slightly
soluble in benzene and alcohols; and soluble in acetone,
chloroform and other chlorinated solvents. It also forms amine
salts of limited solubility in water.
1.3.3 Stability - Brodifacoum is quite stable at room temperature.
1.3.4 Vapour pressure - Very low, less than 1.33 x 10-7 kPa (1 x 10-6
mmHg)/25°C.
1.4 AGRICULTURE, HORTICULTURE AND FORESTRY
1.4.1 Common formulation - Brodifacoum is prepared as a bait (20-50 mg
a.i/kg).
1.4.2 Pests controlled - it is used to control hamsters, mice, rats and
other rodents which have proved difficult to control with
other anticoagulants.
1.4.3 Use pattern - Brodifacoum may be applied wherever rodent pests
have access to the bait. It may be replenished as it is
consumed. It does not usually require more than one feeding for
a kill. Care must be taken to avoid food contamination.
1.4.4 Unintended effects - Brodifacoum is not toxic to plants; if used
as directed it should not be hazardous to wildlife, domestic
animals or humans. Persons with blood coagulation problems and
children should not come in contact.
1.5 PUBLIC HEALTH USE - As in 1.4, for control of nuisance and disease
vector rodent pests.
1.6 HOUSEHOLD USE - As in 1.4, for control of nuisance and disease
vector rodent pests.
2. TOXICOLOGY AND RISKS
2.1 TOXICOLOGY - MAMMALS
2.1.1 Absorption route - Brodifacoum is primarily absorbed from the
gastrointestinal tract; however, dermal absorption may also
occur.
2.1.2 Mode of action - Brodifacoum is an indirect anticoagulant, it
acts through the interruption of the vitamin K1-epoxide cycle,
preventing vitamin K activation rather than depleting its body
reserves.
2.1.3 Excretion products: - No information available.
2.1.4 Toxicity, single dose
Oral LD50:
Rats (M) 0.27 mg/kg b.w. technical material
Mice (M) 0.40 mg/kg b.w. technical material
Rabbits (M) 0.30 mg/kg b.w. technical material
Guinea-pigs 0.28 mg/kg b.w. technical material
Cats 0.25 mg/kg b.w. technical material
Dogs 0.25 mg/kg b.w. technical material
2.1.5 Toxicity, repeated doses - No information available.
2.1.6 Dietary studies - No information available.
2.1.7 Supplementary studies of toxicity - No information available.
2.1.8 Modification of toxicity - No information available.
2.2 TOXICOLOGY - MAN
2.2.1 Absorption route - Brodifacoum may be absorbed from the
gastrointestinal tract and through the intact skin.
2.2.2 Dangerous doses - Because of the low bait concentration and the
nature of the toxic effect, it would require the ingestion of
more than a half-kilogram of bait to produce toxic effects.
Persons with blood coagulation problems should not be exposed to
the pesticide.
2.2.3 Observations of occupationally exposed workers - No information
available.
2.2.4 Observations on exposure of the general public - No information
available.
2.2.5 Observations of volunteers - No information available.
2.2.6 Reported mishaps - No information available.
2.3 TOXICITY - NON-MAMMALIAN SPECIES - Secondary poisoning of owls has
been reported.
3. FOR REGULATORY AUTHORITIES - RECOMMENDATIONS ON REGULATION OF
COMPOUND
3.1 RECOMMENDED RESTRICTIONS ON AVAILABILITY (For definition of
categories, see the Introduction to data sheets)
All available solid formulations are baits of 0.005% or less,
Category 5).
3.2 TRANSPORTATION AND STORAGE
Formulations in Category 5 - Should be transported or stored in
clearly labelled rigid and leakproof containers and away from
containers of food and drink. Storage should be under lock and
key and secure from access by unauthorized persons and children.
3.3 HANDLING
Formulations in Category 5 - Gloves should be used by all those
handling the compound. Adequate washing facilities should be
available close at hand. Eating, drinking and smoking should be
prohibited during handling and before washing after handling.
3.4 DISPOSAL AND/OR DECONTAMINATION OF CONTAINER - Container must be
either burned or crushed and buried below topsoil. Care must be
taken to avoid subsequent contamination of water sources.
Decontamination of containers in order to use them for any other
purpose is not recommended.
3.5 SELECTION, TRAINING AND MEDICAL SUPERVISION OF WORKERS
Formulations in Category 5 - A pre-employment examination is
essential to exclude from contact all persons with blood and
vascular disorders predisposing them to haemorrhaging. Periodic
medical examinations should include tests of blood clotting time,
prothrombin levels, capillary fragility and a record of evidence
of blood in the excreta.
3.6 ADDITIONAL REGULATIONS RECOMMENDED IF DISTRIBUTED BY AIRCRAFT -
Not applicable.
3.7 LABELLING
Formulations in Category 5 - Minium cautionary statement -
"CAUTION"
This formulation contains Brodifacoum, it is poisonous if
swallowed. Keep the material out of reach of children and well
away from foodstuffs, animal feed and food containers. Avoid skin
contact, wear impermeable gloves when handling and wash
immediately after handling. In case of contact, immediately
remove contaminated clothing and wash the skin thoroughly with
soap and water; for eyes, flush with water for 15 minutes. If
poisoning occurs, call a physician. Vitamin K1 is a specific
antidote.
3.8 RESIDUES IN FOOD - Maximum residue levels have not been
recommended by the Joint FAO/WRO Meeting on Pesticide Residues.
4. PREVENTION OF POISONING IN MAN AND EMERGENCY AID
4.1 PRECAUTIONS IN USE
4.1.1 General - Brodifacoum is an anticoagulant of extremely high acute
toxicity to rodents but is considered to be only a slight hazard
to humans. It is primarily absorbed from the gastrointestinal
tract and to some extent through the intact skin. It specifically
reduces vitamin K1 availability in its active form.
4.1.2 Manufacture and formulation - TLV - No information. Closed
systems and forced ventilation are required to reduce, as much as
possible, the exposure of workers to the chemical. All
formulations should be coloured with a warning dye.
4.1.3 Mixers and applicators - When opening a container and when
mixing, protective impermeable boots, clean overalls, impermeable
gloves and a respirator should be worn. Mixing, if not
mechanical, should always be carried out with a paddle of
appropriate length. Avoid contact to mouth and eyes. Before
eating, drinking or smoking, hands and other exposed skin should
be thoroughly washed with alkaline soap. Brodifacoum should not
be used routinely in human dwellings. Baits should not be used
where there is a risk of contaminating food, animal feed or
potable water. Exposed baits should be laid in containers
clearly marked "Poison". Extreme precaution is warranted where
sweetners and attractive colouring are employed in baits. Baits
should not be laid unless all access by children and non-target
animals can be prevented. Except in locked, unoccupied premises
baits should not remain down for more than 24 hours. All exposed
baits and their containers should be removed and burned after
treatment is completed. Rodent bodies should be searched for and
destroyed by burning.
4.1.4 Other populations likely to be affected - With correct use as
described under "Mixers and Applicacor (4.1.3 above) other
populations should not be exposed to hazardous amounts of the
compound.
4.2 ENTRY OF PERSONS INTO TREATED AREAS - Adults may enter immediately
into the premises where baits have been laid down provided
sufficient warning has been given and all exposed baits are
clearly marked "POISON".
4.3 SAFE DISPOSAL OF CONTAINERS AND SPILLAGE - Residues in containers
should be emptied in a dilute form into a deep pit taking care to
avoid contamination of ground waters. Decontamination of
containers in order to use them for other purposes should not be
permitted. Spillage should be removed as much as possible and as
soon as possible into a deep dry pit and the residue washed away
with large quantities of water. The residue and containers may
also be burned in a well-ventilated location.
4.4 EMERGENCY AID
4.4.1 Early symptoms of poisoning - The signs and symptoms of acute
poisoning from a large dose are not likely to be immediately
apparent. When the body's reserves of prothrombin have been
diminished, after two or three days following a single large dose
or a few weeks of repeated ingestion of small doses, bleeding
gums, pallor, swelling and tenderness of the joints, hematomata,
blood in the urine and faeces, and abdominal pains may occur.
Haemorrhagic shock and death may follow in cases of severe
poisoning.
4.4.2 Treatment before a person is seen by a physician - Due to the
delayed appearance of symptoms, it is unlikely that specific
symptoms will be seen directly following exposure. If the
compound has been swallowed, vomiting should be induced
immediately if the person is conscious.
5. FOR MEDICAL AND LABORATORY PERSONNEL
5.1 MEDICAL DIAGNOSIS AND TREATMENT IN CASES OF POISONING
5.1.1 General information - Brodifacoum is an indirect anticoagulant,
an inhibitor of vitamin K1-epoxidase activity. It is extremely
toxic to rodents. It is primarily absorbed from the
gastrointestinal tract and to some extent through the intact
skin.
5.1.2 Symptoms and signs - The onset of clinical signs of poisoning may
be delayed several days after exposure to a single large dose or
after a few weeks of repeated ingestion of small doses. The
signs of poisoning are epistaxis and bleeding gums; pallor and
sometimes petechial rash; massive ecchymoses and/or hematomata
(especially of the articulating joints); blood in urine and
faeces; occasionally paralysis due to cerebral haemorrhage; and
haemorrhagic shock and death.
5.1.3 Laboratory - The principal diagnostic test is a demonstration of
markedly reduced prothrombin activity in blood plasma, as
measured by the method of Quick or one of its modifications. The
test should be repeated at least twice daily until a normal
prothrombin time is established. Also the blood clotting time
and the bleeding time should be measured. Blood is often
demonstrable in the excreta. Secondary anaemia (hypochromic and
microcytic) may be marked.
5.1.4 Treatment - Gastric lavage with tap water should be performed if
the person is treated within a few hours after ingestion of a
single dose. Vitamin K1 is a specific antidote, 5-10 mg of
subcutaneous or intramuscular injection may be repeated if
necessary. Only if the victim is bleeding severely or otherwise
in serious distress should the drug be given intravenously, at a
rate no more than 1 mg/minute. On subsequent days, vitamin K1
therapy should be followed. Small transfusions of fresh whole
blood may be necessary or an immediate and temporary source of
prothrombin and erythrocytes. Vitamin C may be a useful adjunct
to vitamin K therapy, at 100 mg several times a day as necessary.
Following the establishment of control or haemorrhage and the
repair of the coagulation defect, iron replacement therapy should
be initiated to correct the secondary anaemia. In severe
incidences it may also be necessary to aspirate the haematomas
after normal blood clotting has been restored.
5.1.5 Prognosis - If the acute toxic effect is survived, the chances of
complete recovery are very good provided that subdural
haemorrhages or vascular lesions in other tissues do not produce
secondary effects.
5.1.6 References of previously reported cases - No information
available.
5.2 SURVEILLANCE TESTS - Blood clotting time and bleeding time should
be monitored in individuals exposed for long periods of time.
Also, vigilance for blood in the excreta and, peripheral signs of
capillary fragility is appropriate. The blood levels of active
vitamin K1 relative to vitamin K1-epoxidase or, the level of
vitamin K1-epoxidase could also be used to assess overexposure or
the progress of therapy.
5.3 LABORATORY METHODS
5.3.1 Detection and assay of compound -
A. J. Kieboom & C. G. Rammell (1981) Bull. Environs Contam.
Toxicol., 26(5), 674
K. G. Koubek et al. (1979) J. Assoc. Off. Anal. Chem., 62(6),
1297
J. D. Reynolds (1980) Proc. Ann. Mtg. - Am. Assoc. Vet. Lab.
Diagn., 23, 187
L. Von Meyer et al. (1980) Forensic Toxicol. Proc. Eur. Mtg.
Int. Assoc. Forensic Toxicol., pp. 245-251