Herbicides Flashcards
1
Q
Amides
A
- Alachlor
- Bensulide
- Propachlor
- Propanil
2
Q
Benzoic acids
A
- Chloramben
3
Q
Carbamates
A
- Chloropropham
4
Q
Dinitroanilines
A
- Benefin
5
Q
Diphenyl esters
A
- Nitrofen
6
Q
Dipyridyls
A
- Paraquat
- Diquat
7
Q
Nitriles
A
- Dichlobenil
8
Q
Organoarsenicals
A
MSMA (methyl arsonic acid)
9
Q
Phenoxy acids
A
-2,4-D
10
Q
Phtalamic acids
A
Naptalam
11
Q
Thiocarbamates
A
- EPTC
- Triallate
12
Q
Triazines
A
- Atrazine
- Simazine
13
Q
2,4- D source
A
- sprayed on forages at set concentration
- accidental ingestion
- grazing freshly sprayed pastures or lawns
14
Q
2-4D properties
A
- 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
Q
2-4D toxicity causes
A
GI mucosa irritation
16
Q
2-4D toxicity
A
- dogs are the most susceptible, followed by cattle
- acute oral LD50 in dogs is 100 mg/ kg
17
Q
2-4D toxicokinetics
A
- 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
Q
MOA of 2-4D
A
- irritation of GI mucosa
- affects skeletal membranes in dogs
- uncouples oxidative phosphorylation and depresses ribonuclease activity
19
Q
Clinical signs of 2-4D (general)
A
- non specific
- GI and neuromuscular
20
Q
Clinical signs of 2-4D in ruminants
A
- anorexia, rumen atony, bloat, diarrhea, mouth ulcers
- depression, muscle weakness and emaciation with no convulsions
21
Q
Clinical signs of 2 4D in dogs
A
- anorexia, vomitting, and bloody diarrhea
- myotonia and weakness
- rigidity of skeletal muscles
- high doses = rapid onset
22
Q
Lab results with 2,4D
A
- elevated ALP, lactate dehydrogenase and creatinine phosphokinase
23
Q
Diagnosis of 2,4D
A
difficult without history of ingestion
24
Q
Treatment of 2,4D
A
- 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
