Naphthalene/Nicotines/Rotenone Flashcards
Naphthalene is the toxic component of what household item?
mothballs
how many mothballs can cause a toxic reaction in dogs/cats?
just one can be highly toxic!
- 400 mg/kg lowest canine lethal dose
how are animals exposed to naphthalene?
- absorbed through inhalation, orally, dermally, vapor (eye irritation)
- won’t really be absorbed until it hits the intestine if eaten
- people keep moth balls in closet
how does pH affect the absorption of naphthalene?
- acids delay
- bases enhance
it is lipid soluble so the oils increase skin and GI tract absorption
where can we find high concentrations of naphthalene in the body?
- fat, kidneys, liver, lungs
why is naphthalene a risk for fetuses and neonates?
- crosses the placenta
- excreted in milk
how is naphthalene metabolized?
- metabolized in the liver by hepatic enzymes (CYP450)
- metabolites can for epoxides or quinones - reabsorption may cause cellular damage
- metabolites can be conjugated with glutathione to non-toxic substances
- metabolites can be conjugated with sulfate, glucoronic, or mercapturic acid for excretion
how is naphthalene excreted?
primarily through urine but also bile
what is the MOA of naphthalene?
- the oxidative metabolites (oxides) in the circulation can cause hemolysis and methemoglobinemia
- effect is cellular/tissue hypoxia
what are the main clinical signs with naphthalene?
- salivation
- vomiting
- mothball scented breath
- pale or brown gums
- methemoglobinemia, hemolytic anemia, hemoglobinuria
- weakness or lethargy
- labored breathing
- tremors and seizures
what are some things we could see in the lab with naphthalene toxicity?
- hemolysis, heinz bodies
- methemoglobinemia (blood is chocolate brown)
- hemoglobinuria
what can we use to treat severe cases of naphthalene poisoning?
methylene blue 1%
- reduces methemoglobin to hemoglobin
- make sure to use correct dose
- controversial in CATS - can case hemolysis
how is nicotine absorbed?
- readily through MM and resp tract - caustic
- absorption in GIT –> acids delay/bases enhance absorption
what dose of nicotine are clinical signs reported?
1mg/kg
*cigars have 45-150mg
how is nicotine metabolized/excreted?
- liver readily extracts nicotine from circulation
- two principal oxidative metabolites (cotinine and nicotine oxide)
- metabolites are inactive and extracted by the kidneys and excreted in urine
- -> renal excretion is decreased in alkaline or high pH - increased reabsorption
- -> renal excretion increased in acidic or low urine pH