Ivermectin

1
Ivermectin

• Worm medication used orally and parenterally in
  most species (Heartguard, Ivomec, Eqvalen,
  Zimecterin)
• Cumulative toxicant
• Young animals more susceptible
• Often a problem in dogs given horse paste

2
Ivermectin

• Dogs-6ug/kg heartworm preventive dose
• 2.5 mg/kg PO mydriasis, 5mg/kg PO muscle
  tremors, 40 mg/kg PO death
• Collies, Aust. Shepherd, Shelties, Border
  Collies- 0.1 -0.2 mg/kg PO or SC causes toxicity
  and death
• Cats-0.5mg/kgmydriasis and tremors
• Equine-2mg/kgataxia and blindness
• Cattle and Sheep-4mg/kgataxia/death

3
Ivermectin

• Mechanism of action is to increase GABA release,
  affinity of GABA receptor and direct GABA agonist
• Onset time is hours to 1 day, affects CNS
• Clinical signs-hypersalivation (dogs), tremors,
  bradycardia, convulsions, coma, mydriasis,
  blindness, ataxia
• Can see anaphylactic reactions in dogs
• No visible lesions

4
Ivermectin

• Diagnosis
• History of administration
• Brain ivermectin concentration gt100ppb
• Treatment
• Short acting barbiturate for convulsions (no
  benzos)
• IV physostigmine (0.04mg/kg) BID in comatose
  animals
• Flumanezil and moxidectin-expt. Benzo antagonists
• Epinephrine, fluids for anaphylaxis

5
Household Cleaners

• Product warning label indicates level of toxicity
• No label LD50 gt 5 g/kg
• Caution 0.5 5 g/kg
• Warning 50 500 mg/kg
• Danger Poison lt50 mg/kg

6
Soaps, Shampoos, Detergents

• Most have low toxicity
• Usually cause only vomiting and diarrhea
• Cationic surfactants are found in contact lens
  solutions, fabric softeners, swimming pool
  algicides can cause neuromuscular and ganglionic
  blockade as well as GI ulcerations, acidosis and
  shock
• Anionic surfactants are in many cleaning products
  like shampoos have the potential to cause
  hemolysis

7
Disinfectant Cleaners

• Products like Lysol contain phenolic compounds
  mixed with detergents
• Pine oil based compounds like Pine Sol
• These products are especially toxic to cats due
  to metabolism by glucuronidation can cause liver
  injury, jaundice, and renal damage in conjunction
  with GI problems
• Phenolics also found in creosote and tar paper
  watch out for pigs

8
Alkaline Compounds

• Ammonia, Oven Cleaner, Most Drain Openers
• All have pH of gt12 which can cause burns
  (ulcerations)
• Ulcers can be very severe, especially with
  granular drain openers
• Ingestions causes GI ulcerations, vomiting,
  salivation, dysphagia (esophageal stricture),
  dyspnea
• Bleach and scouring powders with bleach usually
  not high enough pH to cause ulceration can be a
  problem if mixed with ammonia chloramine gas

9
Acidic Compounds

• Toilet bowl cleaners, concrete cleaner,
  Lime-A-Way, some drain openers
• Can cause severe burns, but usually not as deep
  as alkali
• Signs and treatment similar to alkaline products

10
Treating Household Cleaner Ingestions

• If a potentially toxic amount of a non-corrosive
  compound ingested, emesis should be induced no
  activated charcoal unless systemic effects are
  expected
• For corrosive compounds 1) dilute with milk or
  water, 2) determine exactly how much of what
  material was ingested

11
Treating Toxic Corrosive Ingestions

• If there is pain, dysphagia, excessive drooling,
  or ulceration and the exposure was potentially
  toxic
• Establish airway and get esophagoscopy
• If esophagus cant be examined quickly, start
  corticosteroids
• If examination indicates burns, give
  corticosteroids
• Symptomatic and supportive care

12
Drano Ingestion Initial Visit
13
Drano Ingestion Final Visit
14
Petroleum Products

• Gasoline, mineral spirits, kerosene, lighter
  fluid, nail polish remover, solvents, motor oil,
  furniture polish
• Biggest worry is aspiration causing hydrocarbon
  pneumonia
• Pneumonia risk related to viscosity less viscous
  more toxic

15
Systemic Toxicity of Hydrocarbons

• Most hydrocarbons are CNS depressants
• Some volatile hydrocarbons sensitize the heart to
  catecholamines and can cause sudden death due to
  cardiac arrest
• Many hydrocarbons cause dermal irritation and
  hair loss

16
Signs of Hydrocarbon Toxicity

• Depression, lethargy, ataxia, seizures, coma
• Dyspnea, coughing, wheezing, X-ray changes in
  lungs with pneumonia
• Spontaneous vomiting and aspiration often occurs
  with more volatile compounds

17
Treating Hydrocarbon Ingestions

• Wash for dermal exposures
• Do not try to increase viscosity by adding
  heavier compound
• Do not induce emesis unless a large, life
  threatening ingestion (gt1 ml/kg)
• Monitor for pneumonia treat with antibiotics if
  present

18
Oak (Acorn) Poisoning

• Red Oak are most toxic due to high tannins, Live
  Oak is questionable
• problems are seasonal, usually in fall after a
  storm or during summer droughts
• primarily affects cattle calves are more
  susceptible
• Toxic priniciple is thought to tannins or their
  metabolites
• Animals must consume large amounts of acorns or
  buds to be toxic

19
Oak poisoning

• Cases have relatively low morbidity with moderate
  mortality (35-80)
• Animals usually ingested acorns for 1 week prior
  to signs
• Symptoms are primarily renal and GI-anorexia,
  depression, weakness and possible nasal
  discharge progresses to rumen atony, black tarry
  diarrhea, ventral edema, dehydration.
• terminal animals are often recumbent near water

20
Cyanogenetic Plants

• Wild and choke cherry, Sudan and Johnson grass,
  Flax, Sugar beet tops, Arrow grass
• contain glycosides with cyanide groups

21
Thiaminases

• Horsetails and Bracken Ferns
• Thiaminases destroy thiamine causing neurological
  problems causes aplastic anemia in ruminants
• Primarily affects horses and ruminants
• Usually occurs if other forage is inadequate

22
Bracken Fern
23
Calcium Oxalate plants

• Members of Araceae family contain calcium
  oxalates Dieffenbachia (Dumb Cane),
  Philodendron, Elephant ear, Calla lily, Arum
  lily, Caladium
• All parts of plant are toxic stalk more toxic
  than leaves
• Usually occurs in cats, dogs, birds, and lizards
• Rarely life-threatening

24
Calcium Oxalate plants

• Preformed calcium oxalate crystals embed in all
  parts of GI tract also contain proteolytic
  enzymes that cause histamine release
• Onset time is immediate primarily affects GI
  system
• Clinical signs include head shaking, salivation,
  dyspnea, vomiting, diarrhea, loss of voice

25
Calcium Oxalate plants

• Diagnosis is by history of exposure and
  compatible clinical signs
• Treatment
• Rinse mouth with water
• Anithistamines for dyspnea
• Demulcents (Kao-pectate no Pepto in cats)
• Fluids for severe vomiting and diarrhea

26
Precatory Bean Rosary Pea

• Grows in Carribean
• Commonly sold as rosary beads
• Extremely toxic, 1 pea can kill a child or dog
• Severe enteritis leads to shock

27
Castor Bean

• Common plant in S. Florida
• Mole plant
• Seeds are extremely toxic due to ricin

28
Oleander

• Contains cardiac glycosides (much like digitalis)
• Highly toxic

29
Cassia

• Coffeeweed, sicklepod
• Causes muscle degeneration

30
Crotalaria

• Rattlebox
• Causes liver injury

31
Cycas and Zamia

• Sago Palms, Coontie Plants
• Seeds are especially toxic
• Causes liver injury

32
Sesbania

• Seeds are most toxic part
• Produce severe hemorrhagic or necrotic enteritis

33
Cestrum

• Day and night blooming jessamine
• Contains Vitamin D
• Kidney damage

34
Lantana

• Causes photosensitization secondary to liver
  injury