Lecture 4 - AntiHelmiths Flashcards

1
Q

Benzimidazoles

A

Mebendazole
Albendazole

Indication: 
nematodes generally (but can be used for certain cestode and trematode infections) 

mebendazole:
active drug; NOT GI absorbed; for infections localized in lumen of gun

Albenadazole:
active drug; GI absorbed; for systemic infections and infections in gut

Stage killed:
eggs, larvae/microfilariae, adults

SE:
GI disturbance, bone marrow suppression

MOA:

1) binds beta-tubulin in inhibit microtubule polymerization
2) inhibit energy production

Albendazole - metabolized by P450 enzymes to active metabolite albendazole sulfoxide

Resistance:

1) switch Beta tubulin isotype 1 (sensitive) to isotype 2 (resistant)
2) point mutation in beta tubulin isotype 1 that changes phenylalanine (wild-type) at position 200

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2
Q

Mebendazole

A

Benzimidazole

indication:
nematodes generally (but can be used for certain cestode and trematode infections) 

mebendazole:
active drug; NOT GI absorbed; for infections localized in lumen of gun

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3
Q

Albendazole

A

Benzimidazole

indication:
nematodes generally (but can be used for certain cestode and trematode infections) 

Albenadazole:
active drug; GI absorbed; for systemic infections and infections in gut

metabolized by P450 enzymes to active metabolite albendazole sulfoxide

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4
Q

What is the indication for benzimidazoles?

A
Indication: 
nematodes generally (but can be used for certain cestode and trematode infections) 

mebendazole:
active drug; NOT GI absorbed; for infections localized in lumen of gun

Albenadazole:
active drug; GI absorbed; for systemic infections and infections in gut

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5
Q

Benzimidazoles kill in what stage?

A

eggs, larvae/microfilariae, adults

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6
Q

What is the MOA of benzimidazoles?

A

1) binds beta-tubulin in inhibit microtubule polymerization

2) inhibit energy production

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7
Q

What resistance is present with benzimidazoles?

A

1) switch Beta tubulin isotype 1 (sensitive) to isotype 2 (resistant)
2) point mutation in beta tubulin isotype 1 that changes phenylalanine (wild-type) at position 200

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8
Q

What are the SE of benzimidazoles?

A

GI disturbance, bone marrow suppression

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9
Q

Ivermectin

A

Indication:
1) onchocerciasis (in combo w/ steroid)
2) lymph filariasis (in combo with albendazole)
Ineffective against trematodes and cestodes

Stages killed:
Larvae/microfilariae

SE:
Mazzotti-like rxn d/t dying microfilariae - use steroids
Contraindicated in loiasis

MOA:
Activates glutamate-gated Cl- channels, causing flaccid paralysis

Resistance:

1) P-glycoprotein up regulation
2) Mutation in glutamate-gated Cl- channels

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10
Q

What is the indication for ivermectin?

A

Indication:
1) onchocerciasis (in combo w/ steroid)
2) lymph filariasis (in combo with albendazole)
Ineffective against trematodes and cestodes

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11
Q

What stages are killed with ivermectin?

A

Larvae/microfilariae

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12
Q

What are the SE of ivermectin?

A

SE:
Mazzotti-like rxn d/t dying microfilariae - use steroids
Contraindicated in loiasis

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13
Q

What is the MOA of ivermectin?

A

MOA:

Activates glutamate-gated Cl- channels, causing flaccid paralysis

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14
Q

What resistance is present in ivermectin?

A

Resistance:

1) P-glycoprotein up regulation
2) Mutation in glutamate-gated Cl- channels

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15
Q

DEC

A

Diethylcarbamazine

Indication:
Nematodes:
A) loiasis
B) lymph filariasis (in combo with albendazole)

Stages killed:
Larvae/microfilariae, adults

SE:

1) Mazzotti-like rxn due to dying microfilariae - use steroids
2) contraindicated in onchocerciasis

MOA:
Stimulate host immune response

Resistance:
Typically none

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16
Q

What is the indication for DEC?

A

Diethylcarbamazine

Indication:
Nematodes:
A) loiasis
B) lymph filariasis (in combo with albendazole)

17
Q

What stage does DEC kill?

A

Diethylcarbamazine

Stages killed:
Larvae/microfilariae, adults

18
Q

What are the SE and contraindications of DEC?

A

Diethylcarbamazine

SE:
Mazzotti-like rxn due to dying microfilariae - use steroids

Contraindicated in onchocerciasis

19
Q

What is the MOA of DEC?

A

Diethylcarbamazine

MOA:
Stimulate host immune response

20
Q

What resistance is present with DEC?

A

Diethylcarbamazine

Resistance:
Typically none

21
Q

Pyrantel pamoate

A

Indication:
Neamatodes in GI lumen

Stages killed:
Larvae, adults

SE:
GI disturbances, HA

MOA: 
1) stim nicotinic receptor 
2) increase ACh release 
3) inhibit acetylcholinesterase 
Mechanisms 1-3 leads to spastic paralysis 

Resistance:
None

22
Q

What is the indication for pyrantel pamoate?

A

Indication:

Neamatodes in GI lumen

23
Q

What stages are killed by pyrantel pamoate?

A

Stages killed:

Larvae, adults

24
Q

What are the SE of pyrantel pamoate?

A

GI disturbances

HA

25
Q

What is the MOA of pyrantel pamoate?

A
MOA: 
1) stim nicotinic receptor 
2) increase ACh release 
3) inhibit acetylcholinesterase 
Mechanisms 1-3 leads to spastic paralysis
26
Q

What resistance is present with pyrantel pamoate?

A

None

27
Q

Praziquantel

A

Indication:
1) trematodes- schistosmiasis
2) cestodes
Ineffective against nematodes

Stage killed:
Immature stages, adults

SE:
GI disturbances, HA

CI:
Intraocular cysticercosis

MOA:
Increase membrane permeability to Ca2+ spastic paralysis

Resistance:
Typically not a problem. Mutation in VGCC?

28
Q

What is the indication for praziquantel?

A

Indication:
1) trematodes- schistosmiasis
2) cestodes
Ineffective against nematodes

29
Q

What stage is killed by praziquantel?

A

Immature stages, adults

30
Q

What are the SE and CI of praziquantel?

A

SE:
GI disturbances, HA

CI:
Intraocular cysticercosis

31
Q

What is the MOA of praziquantel?

A

MOA:

Increase membrane permeability to Ca2+ spastic paralysis

32
Q

What resistance is seen with praziquantel?

A

Typically not a problem

Mutation in VGCC?