A.29 Drugs Against Ectoparasites

Question 1

Organophosphate Drugs to know

Answer 1

Diazinon
Coumaphos

Question 2

Carbamates drugs to know

Answer 2

Propoxur

Question 3

Pyrethroids drugs to know

Answer 3

Permethrin
Deltamethrin
Flumethrin

Question 4

Formamidine drugs to know

Answer 4

Amitraz

Question 5

Types of ectoparasiticides

Answer 5

Adulticides (contact poison or systemic agents)
Insect growth regulators
Repellents

Question 6

Absorption of ectoparasiticides

Answer 6

Slow, but good absorption

Question 7

Distribution of ectoparasiticides

Answer 7

Broad goes through BBB

Question 8

Mechanism of action of ectoparasiticides

Answer 8

GluCl channels (hyperpolarisation and depolarisation)
Acts on Ach receptor

Question 9

Duration of action of : collars, spot on, sprays

Answer 9

4-8 months
4-12 weeks
Days

Question 10

PK of organophosphates

Answer 10

A: good
D: excellent
M: met by liver (partial activation , increase of toxicity)
E: urine & faeces

Question 11

Organophosphate after being metabolised by liver

Answer 11

Diazoxone (much more toxic and longer half life)

Question 12

Mode of action of organophosphate

Answer 12

Contact poison
IRREVERSIBLE inhibition of Ach E

Question 13

Diazinon spectrum:

Answer 13

Fleas, ticks, lice, mites, myiasis

Question 14

Coumaphos spectrum

Answer 14

Varroosis of honey bees

Question 15

Side effects of organophosphate

Answer 15

SLUDGE, bradycardia, bronchoconstriction
Muscle tremor
Seizures, coma

Question 16

Antidote for organophosphate overdose

Answer 16

Atropine
Pralidoxine (Ach E réactivation)

Question 17

Dose of atropine in case of organophosphate overdose

Answer 17

0.2-0.5 mg/kg (1/4 given IV, 3/4 given SC)

Question 18

For which species are organophosphates very toxic

Answer 18

Cats

Question 19

Carbamates mode of actions

Answer 19

reversible inhibition of Ach E

Question 20

Antidote in case of Propoxur overdose

Answer 20

Atropine

Question 21

Spectrum of propoxur

Answer 21

Fleas & ticks

Question 22

1st generation pyrethroids

Answer 22

tetramethrin

Question 23

which generation of pyrethroids is safest

Answer 23

2

Question 24

2nd generation pyrethroids

Answer 24

Permethrin
deltamethrin
flumethrin (varoosis of honey bees)

Question 25

pyrethroid mode of action

Answer 25

repellent & contact poison opens Na channels called "knock down effect"

Question 26

spectrum of pyrethroids

Answer 26

good: ticks, flies & mosquitoes poor: fleas & mange mites

Question 27

toxicity of pyrethroid

Answer 27

Fish cats spot on can be toxic

Question 28

Side effects of pyrethroids

Answer 28

tremors, excitation, MYDRIASIS local irritation & allergy

Question 29

antidote for pyrethroids overdose

Answer 29

none intralipid: prevents drug to reach CNS

Question 30

Amitraz mode of action

Answer 30

MAO - inhibitors (no neurotransmitter uptake) alpha 2 agonists

Question 31

spectrum of Amitraz

Answer 31

8 legged parasites

Question 32

toxicity of Amitraz

Answer 32

narrow TI not to be given to horses, chihuahuas and cats

Question 33

side effects of amitraz

Answer 33

sedation bradycardia hypothermia emesis hyperglycemia

Question 34

antidote for amitraz overdose

Answer 34

Atipamezole

Question 35

which gene mutation can be dangerous whilst giving ectoparasiticides

Answer 35

ABCB1 & MD8 mostly in collies P-glucoprot. cannot pump out drugs from CNS