Agent Name

Warfarin

CAS Number

81-81-2

Formula

C19-H16-O4

Major Category

Pesticides

Synonyms

(Phenyl-1 acetyl-2 ethyl) 3-hydroxy-4 coumarine [French]; 1-(4'-Hydroxy-3'-coumarinyl)-1-phenyl-3-butanone; 200 coumarin; 2H-1-Benzopyran-2-one, 4-hydroxy-3-(3-oxo-1-phenylbutyl)-; 3-(1'-Phenyl-2'-acetylethyl)-4-hydroxycoumarin; 3-(alpha-Phenyl-beta-acetylaethyl)-4-hydroxycumarin [German]; 3-(alpha-Phenyl-beta-acetylethyl)-4-hydroxycoumarin; 4-Hydroxy-3-(3-oxo-1-fenyl-butyl) cumarine [Dutch]; 4-Hydroxy-3-(3-oxo-1-phenyl-butyl)-cumarin [German]; 4-Hydroxy-3-(3-oxo-1-phenylbutyl)-2H-1-benzopyran-2-one; 4-Hydroxy-3-(3-oxo-1-phenylbutyl)coumarin; 4-Idrossi-3-(3-oxo-1-fenil-butil)-cumarine [Italian]; Arab Rat Death; Athrombine-K; Brumolin; CO-Rax; Compound 42; Coumadin; Coumafen; Coumafene; Coumafene [French]; Coumaphene; Coumarin, 3-(alpha-acetonylbenzyl)-4-hydroxy-; Coumarins; Coumefene; Cov-R-Tox; DL-3-(alpha-Acetonylbenzyl)-4-hydroxycoumarin; Dethmor; Dethnel; Dicusat E; Eastern states duocide; Fasco fascrat powder; Frass-ratron; Kumader; Kumadu; Kumatox; Kypfarin; Latka 42 [Czech]; Liqua-tox; Maag rattentod cum; Mar-frin; Martin's mar-frin; Maveran; Mouse pak; Panwarfin; Place-Pax; Prothromadin; Rat & mice bait; Rat-A-way; Rat-B-gon; Rat-Gard; Rat-Kill; Rat-Mix; Rat-O-cide #2; Rat-Trol; Rat-o-cide #2; Rat-ola; Ratorex; Ratox; Ratoxin; Ratron; Ratron G; Rats-No-More; Ratten-koederrohr; Rattenstreupulver Neu Schacht; Rattenstreupulver new schacht; Rattentraenke; Rattunal; Rax; Ro-Deth; Rodafarin; Rodafarin C; Rodex blox; Rosex; Rough & ready mouse mix; Solfarin; Spray-trol brand roden-trol; Temus W; Tox-Hid; Twin light rat away; Vampirinip II; Vampirinip III; W.A.R.F. 42; Warf 42; Warf compound 42; Warfarat; Warfarin Q; Warfarin plus; Warfarin plus [discontinued]; Warfarina [INN-Spanish]; Warfarine [INN-French]; Warfarine [ISO-French]; Warfarinum [INN-Latin]; Zoocoumarin [Netherlands and USSR]; Zoocoumarin [Russian]; d-Con; rac-Warfarin; [ChemIDplus]

Category

Rodenticides, Anticoagulant

Description

Colorless, odorless, crystalline powder. [rodenticide]; [NIOSH]

Sources/Uses

Warfarin and its sodium salt are registered for use in controlling rats and mice; has been used successfully against common vampire bats; a blood anticoagulant; its sodium salt is used medically to treat people with blood hypercoagulation problems; [HSDB] Warfarin competes with vitamin K and inhibits hepatic synthesis of clotting factors to increase the prothrombin time. Typical therapeutic doses are 2 to 10 mg/day. [ACGIH]

Comments

TLV Basis: bleeding; teratogenic; Human NOAEL (no measurable effect on coagulation) = 0.2 mg/day orally; 50% of rats die when exposed to 0.077 mg/kg/day for 90 days; Single doses in humans: not fatal; Ingestion of 1 to 2 mg/kg/day for up to 15 days: fatal to humans; Warfarin crosses the placenta and causes congenital malformations in humans after maternal exposure--63 cases of embryopathy reported; [ACGIH] There is one report of a farmer developing symptoms after prolonged skin contact of a liquid formulation. No other cases after occupational exposure have been reported. [LaDou, p. 609] There are rare case reports of acute liver injury caused by high-dose Warfarin ingestion. [Zimmerman, p. 330] "One study on warfarin in rats has indicated developmental effects. Otherwise, there is no convincing evidence that anticoagulants are teratogenic in experimental animals. There is no evidence to suggest that any anticoagulant rodenticides are mutagenic, but there are insufficient data available on individual compounds to demonstrate an absence of mutagenicity." [Reference #2]

Reference Link

EXTOXNET PIP - WARFARIN

Exposure Assessment
Skin Designation (ACGIH)

Yes

TLV (ACGIH)

0.01 mg/m3, inhalable particulate matter

PEL (OSHA)

0.1 mg/m3

MAK

0.02 mg/m3, inhalable fraction

IDLH (NIOSH)

100 mg/m3

Excerpts from Documentation for IDLHs

Basis for revised IDLH: No inhalation toxicity data are available on which to base an IDLH for warfarin. Therefore, the revised IDLH for warfarin is 100 mg/m3 based on acute toxicity data in humans [Yakkyoku 1977]. This may be a conservative value due to the lack of acute inhalation toxicity data for workers.

Vapor Pressure

0.09 mm Hg

Reference Link

INCHEM: Anticoagulant rodenticides (EHC 175 - 1995)

Adverse Effects
Hepatotoxin

Hepatotoxin, Secondary

Reproductive Toxin

Yes

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Toxicity Information

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Processes

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