pharm head lice

Question 1

MOA malathion

Answer 1

inhibits acetylcholinesterase and causes neuronal hyperstimulation and paralysis

Question 2

how is malathion administered?

Answer 2

topically

Question 3

what are the notable adverse effects of ingestion of malathion?

Answer 3

increased GI peristalsis
miosis
decreased accommodation/pain
rhinorrhea
chest tightness/wheezing
increased lacrimation

Question 4

how would you treat the adverse effects associated with the ingestion of malathion?

Answer 4

atropine and pralidoxime

Question 5

Is malathion pediculicidal only or both pediculicidal and ovicidal?

Answer 5

both pediculicidal and ovicidal

Question 6

what are the most common chemical agents used for head lice?

Answer 6

malathion
permethrin
lindane
ivermectin

Question 7

which drug is the only ovicidal therapy for head lice available?

Answer 7

malathion

Question 8

MOA permethrin

Answer 8

a synthetic pyrethrin that causes hyperexcitability and paralysis by binding voltage-gated sodium channels

Question 9

why has the efficacy of permethrin waned?

Answer 9

knock-down resistance (kdr) mutations of louse sodium channels

Question 10

what is a rare but important side effect of permethrin?

Answer 10

asthma exacerbation in pts allergic to ragweed

Question 11

what happens if some permethrin reaches the systemic system?

Answer 11

it is rapidly inactivated by ester hydrolysis (minimal percutaneous absorption occurs)

Question 12

which drug has been disfavored as a result of its potential for neurotoxicity and its persistence in the environment?

Answer 12

lindane

Question 13

what is the indication for lindane?

Answer 13

only used in pts who can’t tolerate or have fialed first-line treatment w/ safer meds

Question 14

what happens when lindane is absorbed systemically?

Answer 14

acts as a CNS stimulant that promotes seizures (producing adverse effects similar to DDT-blockade of GABA action)

Question 15

which pts are more susceptible to toxic exposure of lindane?

Answer 15

elderly
underweight adults
premature infants

Question 16

what are the black box warnings for lindane?

Answer 16

skin diseases

neonatal prematurity will increase drug systematization

Question 17

lindane is contraindicated in what pts?

Answer 17

pts with uncontrolled seizure disorders

Question 18

MOA of ivermectin?

Answer 18

causes hyperexcitability and paralysis by binding selectively and w/ high affinity to glutamate-gated chloride ion channels present in invertebrate nerve and muscle cells

Question 19

what are some of the adverse effects of ivermectin?

Answer 19

Elevated LFTs & can cross BBB in children (due to immature BBB)
also Bronchial asthma

Question 20

what are some of the physical methods of controlling head lice?

Answer 20

benzyl alcohol 5%
cetaphil liquid cleanser
dimethicone
nit combing
bug busting
shaving your head

Question 21

Which treatement for headlice is disfavored in young people because they have an immature BBB?

Answer 21

ivermectin

Question 22

which drug is a topically applied organophosphate insecticide that is exceedingly safe?

Answer 22

malathion

Question 23

How is malathion excreted?

Answer 23

rapidly converted to inactive metabolites that are excreted by the kidney

Question 24

which head lice drug blocks AChesterase and causes SLUDGEBBB?

Answer 24

malathion

Question 25

what does the acronym SLUDGEBBB represent?

Answer 25

the side effects from excessive cholinergic stimulation

S-salivation
L-lacrimation
U-urination
D-defecation
G-GI symptoms
E-emesis
B-bronchorrhea
B-bronchospasm
B-bradycardia