Head lice treatment

Question 1

How long can lice survive with potential to reinfest?

Answer 1

55 hours

Question 2

What other things/people must you be concerned about when you see a patient with head lice?

Answer 2

People they are in close contact with should be treated. Also, the patient’s bed linens, clothes, etc should be washed and such

Question 3

Lice treatments are pediculicidal and ovicidal. What drug is both? What are the other drugs?

Answer 3

Malathion is both pediculicidal AND ovicidal. The rest of the head lice drugs are pediculicidal ONLY

Question 4

Describe the timing of administration of the pediculicidal drugs

Answer 4

2 or 3 courses of treatment spaced 1 week apart

Question 5

Describe the timing of administration of the pediculicidal/ovicidal drugs (malathion)

Answer 5

1 or 2 courses of treatment spaced 1 week apart

Question 6

MOA of malathion

Answer 6

Lice metabolize it to malaoxon which inhibits Acetyl choline esterase –> paralysis

Question 7

ADE of malathion

Answer 7

SLUDGEBBB
Salivation
Lacrimation
Urination
Defecation
GI symptoms
Emesis
Bronchorrhea
Bronchospasm
Bradycardia

Question 8

If you were to be stupid and eat malathion, how could you treat the symptoms?

Answer 8

Atropine and Pralidoxime

Question 9

Goes without saying but administration of malathion is?

Answer 9

Topical.. Dont eat it!

Question 10

List the head lice drugs

Answer 10

Malathion, Permethrin, Lindane, Ivermectin

Question 11

Permethrin MOA

Answer 11

Binds voltage gated sodium channels on lice (not humans!) –> hyper excitability and paralysis

Question 12

Permethrin ADE

Answer 12

Asthma exacerbation in pts allergic to ragweed

Question 13

Why has efficacy waned for Permethrin?

Answer 13

Knock down resistance in louse sodium channels

Question 14

Very very little Permethrin absorbs percutaneously into human skin. The little that does is harmless because?

Answer 14

It is quickly metabolized by ester hydrolysis

Question 15

Lindane administration?

Answer 15

Shampoo

Question 16

Lindane MOA

Answer 16

Not listed in Sweatman’s document. He just says that it is not often used, only when pts cannot tolerate or have failed first line therapy with safer medication

Question 17

Lindane ADE

Answer 17

Seizures and death if you use if waaayyy too much. Rarely, seizures and death after one use

Question 18

MOA for Lindane causing seizures in people?

Answer 18

Lindane is a CNS stimulant that blocks GABA action (similar to DTT)

Question 19

BBW for Lindane?

Answer 19

Skin conditions and prematurity will increase systemic absorption.. Also, contraindicated in pts with seizure disorders

Question 20

Ivermectin administration?

Answer 20

Oral or topical

Question 21

Ivermectin MOA

Answer 21

Binds glutamate gated chloride ion channels in invertebrate nerve and muscle cells –> hyperexcitability and paralysis

Question 22

Ivermectin ADE

Answer 22

1. Worsens asthma
2. Elevates liver enzymes
3. Crosses BBB in children

Question 23

Ivermectin contraindicated in what population?

Answer 23

Children (their BBB is not developed)