Brodifacoum rodenticide

Palmer RB, Alakija P, Cde Baca JE, et al. Fatal brodifacoum rodenticide poisoning autopsy and toxicologic findings. J Forensic Sci 1999 44 851-855. 

The formulas of some ARs are given in Figure 11.1, where it can be seen that they have some structural resemblance to both dicoumarol and vitamin K in its quinone form. All possess quinone rings linked to unsubstituted phenyl rings. The phenyl rings of the rodenticides confer hydrophobicity, especially in the relatively large and complex molecules of brodifacoum and flocoumafen. The chemical properties of some ARs are given in Table 11.1... 

A number of reports have established the presence of rodenticides in predators and scavengers found dead in the field (see, for example, reports of U.K. Wildlife Incident Investigation Scheme [WHS]). Brodifacoum, difenacoum, bromodiolone, and flo-coumafen have all been found, albeit at low levels in most cases (<1 ppm in liver). Sometimes, more than one type of rodenticide has been found in one individual. The toxicological significance of these residues will be discussed in Section 11.5. 

One study conducted in Britain between 1983 and 1989 was of barn owls found dead in the field 10% of the sample of 145 birds contained anticoagulant rodenticide residues in their livers, and difenacoum and brodifacoum were prominent among them (Newton et al. 1990). In another study, barn owls were fed rats that had been dosed with flocoumafen. It was found that a substantial proportion of the rodenticide ingested by owls was eliminated in pellets (Eadsforth et al. 1991). The authors suggest that exposure of owls to rodenticides in the field may be monitored by analysis of pellets dropped at roosts or regular perching places. 

Newton et al. (1990) fed mice containing brodifacoum to bam owls, and estimated that birds lethaUy poisoned by the rodenticide n = 4) had consumed 0.150-0.182 mg/kg of the compound. The birds died within 6-17 days of receiving a single dose... 

Brodifacoum [56073-10-0] is a substituted 4-hydroxywarfarin with a strikingly prolonged half-life in the human body (50,51). Although used as a rodenticide, it has been ingested by some humans and observed to persist from 50 days to eight months. Its use in humans may be prohibitive because of the excessively prolonged half-life in the body. 

This group of compounds have a 4-hydroxycoumarin ring with different side-chain substituents at the 3-position. Commonly used superwarfarin anticoagulant rodentieides in this group are bromadiolone, brodifacoum, coumate-tralyl, coumafuryl, and difenacoum. Brodifacoum, difena-coum and bromadiolone are three of the most commonly used rodentieides around the world. Brodifacoum is the most frequently used rodenticide in the USA. These rodentieides share most of their physical and chemical characteristics, as well as their toxicokinetics, toxicody-namics, and mechanism of toxicity, and the medical toxicological management is the same for all superwarfarins. 

Felice, L.J., Murphy, M.J. (1989). The determination of the anticoagulant rodenticide brodifacoum in blood serum by liquid chromatography with fluorescence detection. J. Anal. Toxicol. 13(4) 229-31. 

Koubek, K.G., Ussary, J.P., Saulsee, R.E. (1979). High performance liquid chromatographic determination of the rodenticide brodifacoum in rat tissue. J. Assoc. Off. Anal. Chem. 62 1297-1301. 

Weitzel, J.N., Sadowski, J.A., Furie, B.C., Moroose, R., Kim, H., Mount, M.E., Murphy, M.J., Furie, B. (1990). Surreptitious ingestion of a long-acting vitamin K antagonist/rodenticide, brodifacoum clinical and metabolic studies of three cases. Blood 76(12) 2555-9. 

Zurawski, J.M., Kelly, E.A. (1997). Pregnancy outcome after maternal poisoning with brodifacoum, a long-acting warfarinlike rodenticide. Obstet. Gynecol. 90(Pt 2) 672-4. 

An even more important derivative is 3-[3-(4 -bromobiphenyl-4-yl)-1,2,3,4-tetrahydronaphth-l-yl]-4-hydroxycoumarin (brodifacoum, 35). This anticoagulant of exceptional potency is capable of control resistant rodents as well as several noncommensal species. Contrary to first generation anticoagulants, a bait concentration of only SO mg/kg brodifacoum is adequate to give control even in a single feeding for most species. As with other anticoagulants, vitamin K, is an effective antidote. In contrast with other acute rodenticides, symptoms are delayed and no bait shyness is observed (Dubock and Kaukeinen, 1978). Its effectiveness... 

Brodifacoum is a member of the second-generation anticoagulant rodenticides known as superwarfarins (27). This compound and others like it (e.g., bromadiolone and difenacoum) were developed to combat rodent resistance to warfarin (27). 

Redfern R, Gill JE, Hadler MR. Laboratory evaluation of WBA8119 (brodifacoum) as a rodenticide for use against warfarin-resistant and non-resistant rats and mice. J Hygiene 1976 77 419-426. 

Eight anticoagulant rodenticides fiom serum (warfarin, coumafiiryl, coumatetra-lyl, brodifacoum, bromadiolone, chlorophacinone, diphacinone, difenacoum) were baseline resolved on a Cjg column (A = 285 nm) using a 20-min 52/48 ->-87/13... 

Toxic substances including sulfur mustard, an extreme irritant and blister agent used as a military poison ricin, a protein poison isolated from the castor bean rodenticidal tetra-methylenedisulfotetramine, now banned from commerce and rodenticide brodifacoum. 

Brodifacoum [3-(3-(4 -bromobiphenyl-4-yl)-l,2,3,4-tetrahydro naphth-l-yl)-4-hydroxycoumarin] is one of the newer and more potent second-generation anticoagulant rodenticides. It was first introduced in 1977 by Sorex Ltd. of London, and then developed by the Imperial Chemicals Incorporated (ICI) Plant Protection Division (Chalermchaikit et al., 1993). 

Brodifacoum has been marketed in several coxmtries for the control of a wide range of rodent pest species. It is available as a 0.005% pellet for rat and mouse control, a smaller 0.001% pellet for field rodent control, and as 29 g wax blocks for sewer rat control. It is the only anticoagulant rodenticide foxmd to produce 100% mortality in most rodent species after only a 24h dose (Chalermchaikit et al., 1993). Brodifacoum was effective against warfarin-resistant rats and mice in 1984, but the possibility of resistance has been raised (Lund, 1984). 

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