Naphthalene

Question 1

What household product is naphthalene found in?

Answer 1

moth balls

Question 2

T/F: dogs are most sensitive to naphthalene toxicity

Answer 2

False, they are most susceptible but cats are more sensitive

Question 3

T/F: It would take 100 naphthalene mothballs to poison a dog

Answer 3

False, it would take 1

Question 4

Which is FALSE regarding exposure of Naphthalene?
A) chronic exposure can lead to cataracts
B) repeated dermal exposure can cause skin irritations
C) Acids enhance stomach absorption
D) absorbed po, inhaled or dermally

Answer 4

C - acids delay absorption

Question 5

Toxicokinetics of Naphthalene

Answer 5

enters blood after absorption and rapidly distributed to adipose tissue, kidneys, liver and lungs
crosses placenta, excreted in milk

Question 6

How is naphthalene excreted by the body?

Answer 6

metabolized in the liver by hepatic enzyme CYP450
metabolites can form epoxides or quinones - reabsorption may cause cellular damage
metabolites can be conjugated with glutathione to non-toxic substances
metabolites can be conjugated with sulfate, glucuronic or mercapturic acid excreted
excreted through urine and bile

Question 7

MoA of naphthalene

Answer 7

oxidative metabolites (oxides) in circulation cause hemolysis and methemoglobinemia
effect is cellular/tissue hypoxia

Question 8

Clinical Signs of naphthalene

Answer 8

salivation, vomiting, mothball scented breath
pale or brown gums, methemoglobinemia, hemolytic anemia, hemoglobinuria
weakness or lethargy
laboured breathing
tremors and seizures, cataracts

Question 9

What is specific treatment for methemoglobinemia?

Answer 9

ascorbic acid or methylene blue