Rodenticide Flashcards
Cholecalciferol: Forms & Sources
FORMS
o Plant derived: Ergocalciferol (D2)
o Animal derived: Cholecalciferol (D3)
SOURCES:
- Ingestion of rodenticides
- Human medicine ingestion ( psoriasis cream)
- Pet food (Blue buffalo 2010)
Cholcalciferol: Toxic dose (acute vs chronic)
Acute ingestion: Exposure to rat/mouse bait in the backyard.
Chronic ingestion: Kitty that licks psoriasis cream off the owners arm.
o Toxic lethal dose depends on the biochemical form
o Vitamin D3 is 10 times more potent than D2
o Single oral lethal dose ~ 13 mg/kg
0.1 mg/kg mild GI signs
> 0.5 mg/kg hypercalcemia, renal failure
Cholecalciferol: What predispositions make dog more succeptible?
Primary renal failure, Addisons ( animals prone to hypercalcemia)
Cholecalciferol: Mechanism of Toxicity
Vitamin D absorbed/ingested-> LIVER( 25hydroxyvitaminD)-> KIDNEY (1,25-di-hydroxyvitamin D)-> Vitamin D receptors in SI, Colin, & Lungs activated
GUT - Calcium & Phosphorus absorption increase
Kindneys- Calcium renal absorption increases ( increase Phosphorous too)
BONE-If you have low calcium floating around in the body, the Vit D is going to help increase resorption of calcium from the bone, so that you can increase that calcium
Hypercalcemia Differentials
HARD IONS o H: Hypercalcemia of malignancy (lymphoma, multiple myeloma, adenocarcinoma of anal glands) Hyperparathyroidism o A: Addison’s disease, aluminum tox o R: Renal failure – throws off Ca:P ratio o D: Vitamin D tox – vitamin D is needed to absorb Ca. too much vit D = too much Ca absorbed o I: Iatrogenic, Idiopathic o O: Osteolytic disease like HOD (hypertrophic osteodystrophy) o N: Neoplasia (osteosarcoma), metastatic bone disease such as mets from a mammary tumor o S: Spurious
o Hypercalcemia of malignancy o Hypoadrenocrticism o Chronic kidney disease o Primary hyperparathyroidism o Osteolytic bone disease o Ingestion of Vitamin D ointments (psoriasis cream) o Granulomatous disease
Cholecalciferol Toxicity early signs (12-36 hrs)
- Depression, weakness, anorexia
Thennnn
• Vomiting, polyuria/polydipsia, constipation, dehydration – bc we have CS of renal disease
• Dark Feces ( GI ulceration)
Cholecalciferol : Later Clinical signs
• Acute kidney injury, oliguria/anuria
-Calcification of the renal tubules
• ECG changes
-Shortened QT, prolonged PR intervals
• Hematemesis/melena
-Grave prognosis , GI Mineralization and ulceration
Cholecalciferol: What should be monitored in Minimum database?
o Monitor total calcium - 15-18mg/dL (Normal 9.5-11.5) o ionized calcium -calcium/phosphorus product that is greater than 60 - 70 -mineralization o phosphorus o BUN o Creatinine o UA - Isosthenuria
Cholecalciferol : Treatment in acute ingestion
o Acute ingestion (<6 hours)
- Induce emesis
- Activated charcoal
- Monitor calcium at baseline and q 24-48 hours for 5-7 days
Cholecalciferol: What does Supportive care look like for this toxicity
IV fluids - NaCl
- high levels of fluids to correct dehydration, volume expansion, and the sodium will induce calciuresis
Phosphate binders
- if animal is eating, used to bind phosphorus before its absorbed into the system
antiemetic therapy
- animals vomit a lot want to decrease electrolyte disturbances
Antacids
- in case there are Gi ulcers due to mineralization
Cholecalciferol: What does Supportive care look like for this toxicity ( 2)
Glucocorticoids
- decrease calcium absorption from bones & GI. After HARDIONS ruled out. No tumors,
Furosemide
- animal must be well hydrated first
Biphostphonate ( Pamidronate)
- Alendronate: cats use this for Primary Hypercalcemia
- Inhibits osteoclastic bone resorption
- Reduces calcium concentration within 48 hours
- Given as Iv infusion, must have IV fluid bolouses too, because can be Nephrotoxic
Salmon Calcitonin
- Inhibits osteoclast activity reducing resorption of calcium from bones
- Risk of anaphylaxis
Bromethalin: What is it? What systems does in affect?
- Used in Rat, gopher… etc poisoning
- neurotoxic ( w/ no antidote)
Bromethalin Toxic dose
Cats are more sensitive
- LD50 ~0.5 mg/kg in cats
- 5 mg/kg in dogs
o Clinical signs are seen at much lower doses
- Cats ~ 0.2 mg/kg
- Dogs ~1 mg/kg
Bromethalin Toxokinetics : What part of the body is it distributed to most?
Gi tract absorption
- Peak plasma levels 4 hrs
Liver metabolization
- desmethylbromethalin is the toxic metabolite
Throughout body - Highest in Body fat
Bromthalin : Clinical signs of the primary target of the drug. Acute vs Delayed onset
Primary target:CNS
- Depression, abnormal behavior, ataxia, tremors, seizures
Dose dependent clinical signs ACUTE >LD50 2-24 hrs post injection • Severe muscle tremors • Hyperthermia • Seizures • Hyperesthesia
Delayed onset neurological signs Days- 2 weeks, less toxic dose • Hind limb ataxia/paresis • Patellar hyperreflexia • Mild to severe CNS depression • Seizure---- Coma