Lecture 4 - AntiHelmiths Flashcards
Benzimidazoles
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
Mebendazole
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
Albendazole
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
What is the indication for benzimidazoles?
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
Benzimidazoles kill in what stage?
eggs, larvae/microfilariae, adults
What is the MOA of benzimidazoles?
1) binds beta-tubulin in inhibit microtubule polymerization
2) inhibit energy production
What resistance is present with benzimidazoles?
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
What are the SE of benzimidazoles?
GI disturbance, bone marrow suppression
Ivermectin
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
What is the indication for ivermectin?
Indication:
1) onchocerciasis (in combo w/ steroid)
2) lymph filariasis (in combo with albendazole)
Ineffective against trematodes and cestodes
What stages are killed with ivermectin?
Larvae/microfilariae
What are the SE of ivermectin?
SE:
Mazzotti-like rxn d/t dying microfilariae - use steroids
Contraindicated in loiasis
What is the MOA of ivermectin?
MOA:
Activates glutamate-gated Cl- channels, causing flaccid paralysis
What resistance is present in ivermectin?
Resistance:
1) P-glycoprotein up regulation
2) Mutation in glutamate-gated Cl- channels
DEC
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