IPCS INCHEM Home


    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: 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







    See Also:
       Toxicological Abbreviations
       Brodifacoum (HSG 93, 1995)
       Brodifacoum (PIM 077)