Organic Synthetic Herbicides

Question 1

Sources for phenoxy derivatives of fatty acids and typical species to ingest

Answer 1

Freshly sprayed lawns or pastures

• Need to ingest a lot of FRESH toxic grass to get sick
• K9 and Bov typical

Question 2

Physical and chemical properties of phenoxy derivatives

Answer 2

Alter met of plants to ↑ accumulate of Nitrate or Cyanide

• Improves palatability
• Not stable in environment
• DOESNT alter rumen microflora
• GI irritant

Question 3

Toxicokinetics of phenoxy derivatives

Answer 3

Moderate toxicity

• Readily abs from GI, poor from skin
• Wide Vd incl brain
• Meat residues unlikely
• Short HL (longer in K9)
• Met in L, excr in U+
• Alk or U+ enhances excretion

Question 4

MOA of phenoxy derivatives

Answer 4

Uncouple oxidative phosphorylation, ↓ribonuclease synth

• Fx skeletal muscle membranes in K9
• GIT irritant

Question 5

CS and Lesions of phenoxy derivatives

Answer 5

Ruminants (GIT):
-Rumen atony, bloat, diarrhea. No sz
Dogs (GIT+neuro):
-Anorexia, B+y D+
-Weakness of rear muscles, ataxia
-HD: opisthotonos, posterior paralysis
Porcine :
-V+/D+, muscle weakness &↓

Question 6

Dx/Analysis of phenoxy derivatives

Answer 6

• Organ analysis is expensive
• ↑ ALP, LDH, CPK levels
• Dx: Difficult bc CS nonspecific
• Chem analysis may be helpful
• Rule out other dz

Question 7

Tx/Prev for phenoxy derivatives

Answer 7

• No specific antidote
• Detox (AC, bath)
• IV fluids, antidiarrheal and rumenatories

Question 8

Sources for Dipyridyl (Paraquat/Diquat)

Answer 8

• Broad spec dessicant contact herbicide

- Ingest or malicious

Question 9

Physical and Chemical properites of Dipyridyls

Answer 9

• Unstable, rapidly deactivated by light & soil
• Stable in acid, destroy in alk
• Salt sol in H2O, insoluble in hydrocarbon solvents
• Paraquat binds strongly to MM

Question 10

Toxicokinetics of Dipyridyls

Answer 10

• All animals susceptible
• Mod-High toxicity
• Tox enhanced by VitE Deficiency, depletion of tissue glutathione and O2 therapy
• C daily exposure kills K9s
• Diquat poor GI absorption
• Paraquat abs in GI and skin, high conc in the lung
• Excr 24hrs unchanged in urine (minimal metabolism)

Question 11

MOA of Dipyridyls

Answer 11

• Reduced by NADPH to produce singlet O
• > rxn w/ lipids of cell membrane->hydroperoxides formed.

-Free radical membrane damage, cellular degeneration and necrosis (esp lung)

Question 12

CS of ACUTE toxicosis of Diyridyls

Answer 12

V/D, anorexia, depression
high doses may cause ataxia, dyspnea, and seizures
make take 3 days to see CS after exposure to paraquat

Question 13

CS of DELAYED Dipyridyls

Answer 13

resp signs -> tacypnesa, dyspnea, harsh resp sounds, cyanosis, and reduced pulmonary compliance

Question 14

CS of subacute or chronic toxicosis of Dipyridyls

Answer 14

after 7 days-3kws

resp signs due to pulmonary fibrosis

Question 15

Lesions w/ Dipyridyls

Answer 15

• -Pulm fibrosis, edema, hemorrhage, failure of lung to collapse
• -Lingual ulcers may be seen
• -L/K/Spleen congested and enlarged
• Microscopic lesions consistent with gross findings
• EARLY GI, LATER PULMONARY

Question 16

Analysis/Dx of Dipyridyls

Answer 16

• Chem analysis of stomach contents, U+, lung.
• U+ may be negative post 48hrs of exposure
• Radiograph lungs

Question 17

DDx for Dipyridyls

Answer 17

pneumoniasis, inhalant toxicosis

Question 18

Tx/Px of Dipyridyls

Answer 18

No specific antidote
Detox with emetics, Fuller’s Earth DOC, AC as alternative, saline cathartics after adsorbant
-Supportive tx: with fluids, hemodialysis or peritoneal dialysis
-DO NOT GIVE O2!!

• Antioxidants: Orgotein (superoxide dismutase), Acetylcysteine, ascorbic acid, Niacin or riboflavin
• Start tx w/in 24hrs

-Px: Guarded/grave