pharm head lice Flashcards
MOA malathion
inhibits acetylcholinesterase and causes neuronal hyperstimulation and paralysis
how is malathion administered?
topically
what are the notable adverse effects of ingestion of malathion?
increased GI peristalsis miosis decreased accommodation/pain rhinorrhea chest tightness/wheezing increased lacrimation
how would you treat the adverse effects associated with the ingestion of malathion?
atropine and pralidoxime
Is malathion pediculicidal only or both pediculicidal and ovicidal?
both pediculicidal and ovicidal
what are the most common chemical agents used for head lice?
malathion
permethrin
lindane
ivermectin
which drug is the only ovicidal therapy for head lice available?
malathion
MOA permethrin
a synthetic pyrethrin that causes hyperexcitability and paralysis by binding voltage-gated sodium channels
why has the efficacy of permethrin waned?
knock-down resistance (kdr) mutations of louse sodium channels
what is a rare but important side effect of permethrin?
asthma exacerbation in pts allergic to ragweed
what happens if some permethrin reaches the systemic system?
it is rapidly inactivated by ester hydrolysis (minimal percutaneous absorption occurs)
which drug has been disfavored as a result of its potential for neurotoxicity and its persistence in the environment?
lindane
what is the indication for lindane?
only used in pts who can’t tolerate or have fialed first-line treatment w/ safer meds
what happens when lindane is absorbed systemically?
acts as a CNS stimulant that promotes seizures (producing adverse effects similar to DDT-blockade of GABA action)
which pts are more susceptible to toxic exposure of lindane?
elderly
underweight adults
premature infants
what are the black box warnings for lindane?
skin diseases
neonatal prematurity will increase drug systematization
lindane is contraindicated in what pts?
pts with uncontrolled seizure disorders
MOA of ivermectin?
causes hyperexcitability and paralysis by binding selectively and w/ high affinity to glutamate-gated chloride ion channels present in invertebrate nerve and muscle cells
what are some of the adverse effects of ivermectin?
Elevated LFTs & can cross BBB in children (due to immature BBB)
also Bronchial asthma
what are some of the physical methods of controlling head lice?
benzyl alcohol 5% cetaphil liquid cleanser dimethicone nit combing bug busting shaving your head
Which treatement for headlice is disfavored in young people because they have an immature BBB?
ivermectin
which drug is a topically applied organophosphate insecticide that is exceedingly safe?
malathion
How is malathion excreted?
rapidly converted to inactive metabolites that are excreted by the kidney
which head lice drug blocks AChesterase and causes SLUDGEBBB?
malathion
