L4. Long Acting Anticoagulants Flashcards

1
Q

Pesticides

A

Rodenticides

Insecticides

Molluscicides

Avicides

Herbicides

Fungicides

Algaecide

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2
Q

Rodenticide Risk:

A

Rats, mice, gophers, moles

Dangerous becuase they are designed to be both attractive to and lethal to mammals

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3
Q

Rodenticide Types

A

Anticoagulants

bromethalin

cholecalciferol

Strychnine

Zinc phosphide

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4
Q

Anticoagulants

A

Previously the most commonly used

Primarily affects dogs and wildlife

Other species occasionally affected

EPA made a large change in the last few years

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5
Q

Anticoagulants:

First Generation

A
  • Warfarin:
    • identified as Wisconsin Animal Research Farm
    • Form dicoumarol found in hemorrhagic disease of cattle
    • Grazing moldy sweet clover
  • Diphacinone
    • tomcat
    • ramik
  • Mousemaze
  • Chorophacinone
    • rozol
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6
Q

Anticoagulants:

Second Generation

A
  • Efficacious agianst warfarin resistant rats
  • Typical concentration is 0.005%
  • Brodifacoum
    • talon, havoc, bolt, volid, D-con mouse pruf2
  • Diphethialone
    • D-cease, hombre, generation
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7
Q

Anticoagulants:

Second Gen

Tox

A

More potent

longer acting

Potential for relay toxicosis

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8
Q

Toxicokinetics

A

Oral absorption levels peak in minutes to hours

Plasma Half life:

warfarin - 14 hrs

Diphacinone - 4.5 days

Brodifacoum - 6 days

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9
Q

Normal Clottng Mechanism

A
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10
Q

Anticoagulant:

Mechanism of Action

A

Vitamin K1 is regenerated by Vitamin K1 epoxide reductase

Anticoagulants block this recycling

Also interfere with utilization by blocking synthesis of Vit. k dependent clotting factors

Factor Vll (PT) affected early

Factor lX (ptt) later on

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11
Q

Interference with vitamin K

A
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12
Q

Anticoagulants

Toxicity

A
  • Acute oral LD50 in dog
  • Warfarin 20-300
  • Brodifacoum
  • Bromadiolone
  • Diphacinone

Start Therapy if dosage estimate is ¼ of LD10

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13
Q

Anticoagulant

Risk Factors

A
  • geriatric or neonatal animals
  • Concurrent liver diaseas
  • Ruminats, horses – moldy sweet clover
  • Protein displacing drugs
    • phenylbutazone
    • Also Corticosteroids, Aspirin
    • Impaired platelet function or low counts
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14
Q

Anticoagulants

Kinetics

A
  • 1st generation has ½ lives of several hours
    • effects last a few day
  • 2nd gen has ½ lives of several days
    • effects last 12-30 days
  • Drugs that suppress liver metabolism inreases duration
    • cimetidine, sulfonamides, fluconazole, phenylbutazone
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15
Q

Anticoagulants:

Delayed Effects

A

Depletion time for active Vitamin K

Half life of K dependent clotting factors

Clinical coagulopathy usually form 6 days post ingestion

As short as 36hr

PT drops first, ptt later

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16
Q

Anticoagulants:

Clinical Effect

A

Related to hemorrhage and blood loss

Often weak, anemic, dyspnea, epistaxis,

Melena, lameness, ataxia

Occasional CNS signs

Hemothorax

May be acute death with no early signs

17
Q

Anticoagulants,:

Necropsy Lesions

A

Hemorrhage, hematomas, hemothorax

Hemarthrosis, subdural hematomas

Occus in a variety of tissues, organs, spaces

platelet function normal

18
Q

Anticoagulants:

Clinical Picture

A

Clinical signs delayed

Initial signs are non-specific

Lethargy, depression, pallor

Varied Sx of bleeding tendency

Anemia

Melena, bloody vomit/diarrhea, point/area bleeding on mucous membranse, epistaxis, hematomas

Bleeding into joints/sc bleeding in feet can cause lameness

persistent bleeding form venipuncture sites

19
Q

Anticoagulant:

Diagnosis

A

Presence of hemorrhagic syndrome

Clotting time prolonged

Prothrombin time post exposure

Activated partial thromboplasitn time

PIVKA – proteins induced by Vit K antagonists (Thrombotest)

Detects precursor proteins of clotting factors

20
Q

Diagnostics

A

Detection of acitve ingredient in liver, blood, bait

Liver: sample of choice in deceased animals

Blood: Sample of Choice in live animals

Hay: for dicoumarol

21
Q

Clinical Patholgy

A

Regenrative / non-regenerative normocytic, normochromic anemia

Often leukocytosis

+/- thrombocytopenia

Abnormal clotting profile

One-stage prothrobim time

Activated parital thromboplasitn time

Thromin time

Activated clotting time

22
Q

Differential DIagnosis

A

Dicoumarol - livestock via moldy hay

Idiopathic coagulopathy

Autoimmune thrombocytopenai

DIC
Hereditary

Liver disease

23
Q

Treatment

A

Supportive

Releive hemothroax, raise PCV, Rx shock

Vitamin K1 (Vit K3 ineffective)

Oral route with fatty food prefered

Time lag 3-6+ hours for effetive coagulation

Vit K1 has a high incidence of anaphylaxis when given IV

When phytonadione is used orally with a high fat meal rapid absorption and acitvation of phytonadione is nearly equal to IV administration