Dipyridyl Herbicides (Paraquat and Diquat) Flashcards Preview

Toxicology > Dipyridyl Herbicides (Paraquat and Diquat) > Flashcards

Flashcards in Dipyridyl Herbicides (Paraquat and Diquat) Deck (39)
Loading flashcards...
1
Q

What is an example of a broad-spectrum desiccant contact herbicide?

A

Dipyridyl herbicides

2
Q

What are concentrated forms of dipyridyl herbicides used for?
Dilute forms?

A
  • Agricultural use

- Lawns and gardens

3
Q

What is the concentration of dipyridyl herbicide used for agricultural use?

A

0.5 lb/acre

4
Q

What are 2 potential sources of dipyridyl herbicide toxicity?

A
  • Ingestion of concentrates

- Malicious

5
Q

Are dipyridyl herbicides stable?

A

No

6
Q

T/F: Dipyridyl herbicides are rapidly inactivated by light and soil.

A

True

7
Q

What type of an herbicide is paraquat?

A

Dipyridyl herbicides

8
Q

Are dipyridyl herbicides soluble in water?
Alcohol?
Hydrocarbon solvents?

A
  • Water: yes
  • Alcohol: poorly soluble
  • Hydrocarbon solvents: no
9
Q

In what type of environment are dipyridyl herbicides stable in?
destroyed by?

A
  • Stable: neutral or acid

- Destroyed by: alkali

10
Q

Which dipyridyl herbicide binds strongly to soil?

A

Paraquat

11
Q

Dipyridyl herbicides are caustic to what?

A

Mucous membranes

12
Q

Which animals are susceptible to dipyridyl herbicides?

A

All animals are susceptible especially dogs.

13
Q

What is the oral LD50 range in cats, dogs, pigs, sheep and humans?

A

25-75 mg/kg

14
Q

Toxicity of paraquat is enhanced by what 3 things?

A
  • Selenium/Vitamin E deficiency
  • Depletion of tissue glutathione
  • Oxygen therapy
15
Q

Daily oral exposure to what level of paraquat causes chronic toxicity and death in dogs?

A

170 ppm

16
Q

How is paraquat absorbed by the GIT?

A

Poorly absorbed

17
Q

Where is paraquat distributed in high concentrations?

A

Lungs

18
Q

Paraquat is excreted in what amount of time?

How?

A
  • Within 24 hours

- Unchanged in urine

19
Q

Which herbicide is reduced by nicotinamide-adenine dinucleotide phosphate (NADPH) to produce singlet oxygen which reacts with lipids of the cell membranes to form hydroperoxides?

A

Dipyridyl herbicides

20
Q

What are 3 clinical signs that can be seen with acute dipyridyl toxicosis?

A
  • Vomiting
  • Anorexia
  • Depression
21
Q

What are 3 things an acute high dose of dipyridyl herbicide can cause?

A
  • Ataxia
  • Dyspnea
  • Seizures
22
Q

Signs may not be observed until how long after exposure to paraquat?

A

3 days

23
Q

Delayed signs can be seen how long after dipyridyl herbicide exposure?
These can include what signs?

A
  • 2-7 days

- Respiratory signs: tachypnea, dyspnea, harsh respiratory sounds, cyanosis, reduced pulmonary compliance

24
Q

Subacute or chronic toxicosis can be seen how long after exposure to dipyridyl herbicides?

A

7 days to 3 weeks

25
Q

What type of clinical signs are seen with subacute or chronic dipyridyl herbicide toxicosis?

A

Respiratory signs due to progressive pulmonary fibrosis.

26
Q

Where are lesions mainly found with dipyridyl herbicide toxicity?
What can also be seen?

A
  • Respiratory tract

- Lingual ulcers

27
Q

Which 3 organs may be congested and enlarged with dipyridyl herbicide toxicity?

A
  • Liver
  • Kidney
  • Spleen
28
Q

Specimens for chemical analysis can be taken from suspected plant, stomach contents and urine in acute cases or lung in chronic cases of what type of toxicity?

A

Dipyridyl herbicide

29
Q

What type of radiographical changes can be seen with dipyridyl herbicide toxicity?

A

Mild changes in the lungs

30
Q

Diagnosis of dipyridyl herbicides can be made with what 4 things?

A
  • History
  • Clinical signs
  • Lesions
  • Laboratory
31
Q

Dipyridyl herbicide toxicity needs to be differentiated from what 2 things?

A
  • Pneumonias

- Inhalant toxicants such as toxic gases, vapors and dusts

32
Q

Are there any specific antidotes for dipyridyl herbicide toxicity?

A

No

33
Q

What kind of herbicide is diquat?

A

Dipyridyl herbicide

34
Q

What is the preferred form of detoxification for dipyridyl herbicides?

A

Activated Charcoal

35
Q

What is contraindicated for supportive care with dipyridyl herbicide toxicity due to the possibility that it may increase toxicity?

A

Oxygen

36
Q

What can be used to cause diuresis and to support kidney function with dipyridyl herbicide toxicity?

A

Fluid therapy

37
Q

What are 4 biochemical antagonists that can be used to treat dipyridyl herbicide toxicity?

A
  • Orgotein (superoxide dismutase)
  • Acetylcysteine
  • Ascorbic acid
  • Niacin or riboflavin
38
Q

Treatments for dipyridyl herbicide are not likely to be much help unless begun within what amount of time?

A

24 hours of exposure

39
Q

What is the prognosis for dipyridyl herbicide toxicity?

A

Guarded or grave