Phenoxy derivatives of fatty acids (2,4-D) Flashcards Preview

Toxicology > Phenoxy derivatives of fatty acids (2,4-D) > Flashcards

Flashcards in Phenoxy derivatives of fatty acids (2,4-D) Deck (26)
1

3 sources of exposure

  • Accidental ingestion of concentrates or sprays (cattle)
  • Grazing freshly sprayed pastures (cattle)
  • Access to freshly sprayed lawns (pets)

2

T/F: Generally, srayed forages in the recommended concentrations do not cause poisoning

TRUE

3

What do phenoxy derivatives of FAs do to plant metaboisms?

Alter the metabolism of plants--> increases their toxicity by increasing accumulation of nitrate or cyanide

4

T/F: Phenoxy derivatives of FAs also decrease palatability of some poisonous plants, decreasing poisoning

FALSE--they increase palatability of some poisonous plants, increasing poisoning

5

Are phenoxy derivatives of FAs stable in the environment?

NO

6

Are phenoxy derivatives of FAs degraded by rumen flora, thus altering it?

Nope

7

T/F: Phenoxy derivatives of FAs are an irritant to GI mucosa

TRUE

8

Which species are the most susceptible to phenoxy derivatives of FAs?

Cattle and dogs

9

T/F: Cattle are more sensitive to phenoxy derivatives of FA's than other species

FALSE--it's dogs

10

What does toxicity depend on?

Species and duration of exposure

11

What's the acute oral LD50 in dogs?

Approximately 100mg/kg

12

Where are phenoxy derivatives of FAs readily absorbed from? Where are they poorly absorbed from?

  • Readily absorbed from GI tract or by inhalation
  • Poorly absorbed from skin

13

Where are phenoxy derivatives of FAs distributed?

All over body, including liver, kidney, and brain

14

T/F: Meat residues in cattle and sheep are likely even with exposure to low concentrations of 2,4-D

FALSE--residues unlikely unless exposed to very high concentrations

15

What are the half lives of phenoxy derivatives of FAs?

Generally short (few hours), but longer in dogs (up to 3-4 days)

16

How is 2,4-D mainly metabolized? How is it excreted?

  • Metabolized mainly by hydrolysis
  • Excreted mainly unchanged in urine by tubular secretion

17

T/F: Alkalinization of urine enhances renal excretion

TRUE

18

Mechanism of action (3)?

  • Irritation of GI mucosa
  • Affect skeletal muscle membranes in dogs
  • Uncouple oxidative phosphorylation, and depress ribonuclease synthesis (unknown relationship to clinical signs)

19

What are the general clinical signs of 2,4-D toxicity?

Generally non-specific; mainly GI and NM

20

Clinical signs in ruminants?

  • Anorexia, rumen atony, may be bloat and diarrhea and ulcers in buccal mucosa
  • Depression, muscle weakness and emaciation with no convulsions

21

Clinical signs in dogs?

  • Anorexia, vomiting, bloody diarrhea
  • Myotonia and weakness of the muscles especially posterior muscles and ataxia w/ rigidity of skeletal muscles
  • At high doses, onset is rapid (

22

Clinical signs in swine?

Vomiting, diarrhea, muscle weakness and depression

23

Various lesions of 2,4-D toxicosis?

  • Nonspecific
  • Mainly GI damage and degeneration of liver and kidney
  • Rumen stasis with ingested food is a characteristic finding

24

Laboratory diagnosis?

  • Elevated ALP, LDH, CPK
  • Chemical analysis
    • Analytical methods are expensive and time consuming
    • Specimens are suspected forage, water, kidney, urine, liver, stomach, feces

25

Diagnosis?

  • Difficult from clinical signs and lesions b/c they are nonspecific
  • History of ingestion is important
  • Chemical analysis might be helpful
  • Rule out other diseases

26

Treatment?

  • No specific antidote
  • Detoxification
    • Wash skin w/ soap + water
    • Activated charcoal
  • Supportive/symptomatic treatment
    • IV fluids
    • Antidiarrheals and rumenatorics