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Flashcards in Herbicides Deck (45):
1

Amides

- Alachlor
- Bensulide
- Propachlor
- Propanil

2

Benzoic acids

- Chloramben

3

Carbamates

- Chloropropham

4

Dinitroanilines

- Benefin

5

Diphenyl esters

- Nitrofen

6

Dipyridyls

- Paraquat
- Diquat

7

Nitriles

- Dichlobenil

8

Organoarsenicals

MSMA (methyl arsonic acid)

9

Phenoxy acids

-2,4-D

10

Phtalamic acids

Naptalam

11

Thiocarbamates

- EPTC
-Triallate

12

Triazines

- Atrazine
- Simazine

13

2,4- D source

- sprayed on forages at set concentration
- accidental ingestion
- grazing freshly sprayed pastures or lawns

14

2-4D properties

- alter metabolism of plants
- increases plant accumulation of nitrate or cyanide
- not stable in environment
- not degraded by rumen flora
- can make poisonous plants more palatable

15

2-4D toxicity causes

GI mucosa irritation

16

2-4D toxicity

- dogs are the most susceptible, followed by cattle
- acute oral LD50 in dogs is 100 mg/ kg

17

2-4D toxicokinetics

- Absorbed by GI or inhalation, not skin
- distributed throughout the body
- meat residue unlikely
- half life is short in all species except dogs
- excreted in urine

18

MOA of 2-4D

- irritation of GI mucosa
- affects skeletal membranes in dogs
- uncouples oxidative phosphorylation and depresses ribonuclease activity

19

Clinical signs of 2-4D (general)

- non specific
- GI and neuromuscular

20

Clinical signs of 2-4D in ruminants

- anorexia, rumen atony, bloat, diarrhea, mouth ulcers
- depression, muscle weakness and emaciation with no convulsions

21

Clinical signs of 2 4D in dogs

- anorexia, vomitting, and bloody diarrhea
- myotonia and weakness
- rigidity of skeletal muscles
- high doses = rapid onset

22

Lab results with 2,4D

- elevated ALP, lactate dehydrogenase and creatinine phosphokinase

23

Diagnosis of 2,4D

difficult without history of ingestion

24

Treatment of 2,4D

- no specific antidote
- detox (wash skin and activated charcoal)
- supportive

25

Dipyridyl (Paraquat) is stable or unstable in the environment

unstable, inactivated by light and soil

26

Solubility from greatest to least of paraquat

- most soluble in water
- poorly soluble in alcohol
- insoluble hydrocarbon solvents

27

When is paraquat stable in the environment

- acidic or neutral conditions
- destroyed by alkali

28

Paraquat binds strongly to

- soil

29

Paraquat is caustic to

mucous membranes

30

Paraquat toxicity

- dogs are especially susceptible
- Oral Ld50 = 25-75 mg/ kg
- daily exposure 170 ppm= chronic tox and death in dogs

31

What enhances paraquat toxicity

- Vitamin E and selenium def.
- depletion of tissue glutathione
- oxygen therapy

32

Diquat is well or poorly absorbed from the GI tract

poorly

33

Paraquat is absorbed from

- 20% GI
- 10% skin

34

Paraquat distribution and accumulation

- distributes all over the body
- concentrated in the lung

35

How is paraquat excreted

- urine with minimal metabolism

36

MOA of paraquat

- reduced by NADPH and makes singlet oxygen (ROS signs)

37

Acute toxicosis with paraquat

- Early = vomiting, anorexia, depression, ataxia, dyspnea, seizures
- Delayed signs focus more on lung signs

38

How long can it take for signs of paraquat poisoning to manifest

- 3 days

39

Lesions from paraquat

- mainly in the respiratory tract
- lingual ulcers
- liver, spleen and kidney can be congested

40

Lab findings with paraquat

- can check plant, stomach content and urine
- urine = negative after 48 hrs

41

treatment for paraquat poisoning

- no specific antidote
- detoxification (activated charcoal preferred)

42

Products used for detox in paraquat poisoning

- emetics
- activated charcoal
- bentonite or fullers earth orally several times per day
- saline cathartics following the adsorbent

43

Supportive treatement for paraquat poisoning

- NO oxygen
- fluid therapy to help kidney function
- hemodialysis

44

Biochemical antagonists of paraquat

- Orgotein (superoxide dismutase)
- acetylcysteine
- asorbic acid
- niacin or riboflavin

45

What is the time frame for treatment with paraquat poisoning

- within 24 hours
- prognosis is guarded or grave