GI pharmacology (Fitz)

Question 1

albendazole and mebendazole are used for these helminths:

Answer 1

nematodes and cestodes

Question 2

praziquantel is used for these helminths:

Answer 2

cestodes and trematodes

Question 3

pyrantel pamoate, diethylcarbamazine, and ivermectin are used for these helminths

Answer 3

nematodes

Question 4

niclosamide used for this hleminth

Answer 4

cestodes

Question 5

these soil-transmitted helminths are among most prevalent worldwide

Answer 5

ascaris, hookworm, trichuris

Question 6

list the anti-helminthic Benzimidazoles

Answer 6

albendazole and mebendazole

thiabendazole (cutaneous only)

Question 7

MOA of Benzimidazoles?

Answer 7

disrupt microtubule dynamics

bind to parasite B-tubulin, disrupt microtubule polymerization and microtubule dependent processes

Question 8

this Benzimidazole has poor solubility, POOR ABSORPTION, plus efficient metabolism and protein binding which leads to LOW SYSTEMIC EXPOSURE

Answer 8

Mebendazole

safe and effective: single dose (child > 2 and adult)

Question 9

This Benzimidazole has modest absorption, EFFICIENT METABOLISM, low systemic exposure to parent drug

Answer 9

Albendazole

Question 10

this Benzimidazole’s systemic toxicity limits its use and is for CUTANEOUS USE ONLY (For larval migrans)

Answer 10

Thiabendazole

Question 11

this drug is for Enterobius vermicularis-Pinworm

Answer 11

Mebendazole

Pinworm a common infx in US children

Question 12

this drug for Necator americanus and Ancylostoma duodenale-Hookworm

Answer 12

Albendazole

Question 13

these drugs for Ascaris lumbricoides

Answer 13

Albendazole

Mebendazole

Question 14

these drugs for Trichuris trichiura-Whipworm

Answer 14

Mebendazole: 3 day course most effective

Albendazole

Question 15

this drug for Toxocara spp, Larval migrans

Answer 15

Albendazole

Question 16

a single dose of oral albendazole, mebendazole, and pyrantel pamoate show high cure rates against ___

Answer 16

A lumbricoides

Question 17

for __ infx, albendazole was more efficacious than mebendazole and pyrantel pamoate

Answer 17

hook worm

Question 18

are albendazole and mebendazole teratogens?

Answer 18

yes

embryotoxic and teratogenic and not recommended for use in pregnancy (category C)

Question 19

This alternative or adjuntive nematode therapy is effective against hookworm, pinworm, and roundworm but ineffective against Trichuris trichuria

Answer 19

Pyrantel pamoate

Question 20

how does Pyrantel cause spastic paralysis of the worm?

Answer 20

it is a depolarizing NM blocking agennt. Causes persistent activation of N-AChRs

Question 21

this nematode/helminth drug is used against intestinal strongloidyiasis (thread worm) and Onchocerciasis (river blindness)

Answer 21

Ivermectin

Question 22

this anti-helminth activated glutamate-gated Cl channels which causes Cl current, hyperpolarization, and paralysis of the body wall and pharyngeal muscle in nematodes with no impact on mammals since it cannot cross BBB

Answer 22

Ivermectin

Question 23

Ivermectin can act on this channel in humans and is contraindicated when the BBB is disrupted

Answer 23

GABA-gated Cl channels

Question 24

the most extensive use for ivermectin in humans has been for ___

Answer 24

onchorcerciasis control in africa

river blindness

also useful for lymphatic filiariasis –> Wuchereria bancrofti and Brugia malayi

Question 25

this drug is only available via CDC in the US for lymphatic filiariasis and Loasis. it has signficiant toxicity d/t host response following death of parasites

Answer 25

diethylcarbamazine

Question 26

this is the drug of choice for all adult form tapeworm infx

Answer 26

Praziquantel T solium-pork T saginata-beef D latum-fish

Question 27

This is the drug of choice for larval forms of tapeworm infx

Answer 27

Albendazole ``` cysticercosis Echinococcus granulosus (cystic hydatid disease) ``` Longer tx duration 1-6 months, risk of hepatotoxicity

Question 28

drug of choice for Cysticercosis: Taenia solium tapeworm

Answer 28

albendazole

Question 29

this drug is contra-indicated for tx of ocular cysticercosis-destruction of the org in the eye may damage th eeye

Answer 29

praziquantel

Question 30

this is the drug of choice for cystic hydatid disease d/t Echinococcus granulosus (dog tapeworm in human)

Answer 30

Albendazole-3 month tx or longer

Question 31

this is the drug of choice for all forms of schistosomiasis

Answer 31

praziquantel eggs in intestine, flukes in liver

Question 32

Absorption of praziquantel? Distribution? Metabolism?

Answer 32

Rapidly absorbed Distributes into CF short 1/2 life (1-3 hrs), extensive protein binding, inactive metabolites

Question 33

MOA of praziquantel?

Answer 33

interfere with Ca homeostasis and causes flaccid paralysis in adult flukes causes Ags within the parasite to be exposed to the action of host Abs

Question 34

List anti-protozoal agents

Answer 34

metronidazole tinidazole nitazoxanide

Question 35

list anti-amebic agents

Answer 35

iodoquinol diloxanide furoate paromomycin

Question 36

__ is extensively used to tx infx caused by anaerobic orgs including protozoa/amoebas such as Entamoeba histolytica and Giardia lamblia

Answer 36

metronidazole also bacteria such as Enterococcus spp and clostridium spp

Question 37

how are metronidazole and tinidazole selectively toxic toward microaerophilic pathogens?

Answer 37

these orgs rely on metabolism by pyruvate-ferredoxin oxidoreductase (PFOR) complex --> This activates Metronidazole

Question 38

___ is the drug of choice for amebiasis

Answer 38

Metronidazole

Question 39

__ is approved for the tx of giardiasis as a single 2-g dose and is appropriate 1st line therpay, considered superior to metronidazole

Answer 39

tinidazole

Question 40

adverse effects of metronidazole and tinidazole?

Answer 40

Metallic taste | Disulfiram-like rxn

Question 41

symptomatic, or invasive colitis is treated with ___

Answer 41

metronidazole, followed by a luminal amebicide such as paromomycin, diiodohydroxyquin, or diloxanide furoate to eliminate intraluminal cysts

Question 42

this is the drug of choice for colonization of intestine with E histolytica and an alternative to metronidazole for E histolytica infx during pregnancy

Answer 42

Paromomicin

Question 43

symptomatic pts with giardiasis should be tx with __ as drugs of choice

Answer 43

TINIDAZOLE, metronidazole, or nitazoxanide