antiparasitics

Question 1

nitroimidazoles –> metronidazole

Answer 1

use: GET GAP on the Metro

giaria, entamoeba, trichomonas, gardnerella vaginalis, anaerobes (below the diaphragam- bacteroides, c.diff), H. pylori

Question 2

MOA/ toxicity of metro

Answer 2

MOA= generation of free radicals that create cytotoxic intermediates –> inhibit DNA synth

toxicity= disulfram like reaction, metallic taste, ha, nausea

Question 3

what drugs are related to metro?

Answer 3

nitazoxinide –> cryptosporidiosis

tinidazole –> longer t1/2, better tolerated

Question 4

paramycin - use, moa, tox

Answer 4

• aminoglycoside abx
• use: entamoeba histolytic, leishmania donovani, giardia
• MOA= binds30s ribosome –> inhibits protein synthesis
• concentrates in gut
• minimal toxicity

Question 5

t/f: metronidazole and paromycin are bactericidal?

Answer 5

true.

Question 6

pentamidine - use

Answer 6

treatment/ proph for PCP in patients with SULFA allergies

Question 7

pyrimethamine - use, moa

Answer 7

anti-folate –> impairs DNA synth

use: malaria, toxo

Question 8

benzimidazoles- use

Answer 8

mebendazole, albendazole
-use: nematodes –> ascaris, necator (hookworm), enterobius (pinworm, trichuriasis (whipworm); cestobes –> echinococcus, taenia solium

Question 9

when would you use albendazole for taenia solium?

Answer 9

in setting of neuroxystecercosis

Question 10

MOA of benzimidazoles

Answer 10

inhibits MT assembly

• binds interface of alpha beta tubulin dimer
• selectively binds to parasite tubulin
• *widespread resistance

Question 11

pyrantel pamoate - use, moa

Answer 11

use= nematodes –> roundworm and hookworm

MOA= ACh receptor agonist – causes spastic paralysis of worms, which is pretty cool if you think about it.

Question 12

Praziquentel - use, moa, CI

Answer 12

use: cysticercosis (pork worm), echinococcus (cystic hydatid dz), flukes

MOA= ca++ ionophore –> induce paralysis, detachment and excretion

• causes tegmental damage
• activates host immune system

can cause permanent damage in neurocysticercosis!!!!

Question 13

drugs used in malaria are….?

Answer 13

quinolones
quinine
atovaquone with proguanil
artemisin

Question 14

what is the MOA of quinolones/ what do they treat?

Answer 14

• Malaria
• MOA= acts again erythrocytic stage of infx, blocks detoxification of heme (hematin to hematazoin) via heme polymerase –> build up of heme is toxic to parasite

***falciparum evolved efflux pump resistance

Question 15

quinolones by use/ toxicity

Answer 15

chloroquine= all but falciparum
-toxicity= retinopathy, pruritis, haptotoxicity, cardiac do 

primaquine= hypnozoites in ovale/vivax
-EXCLUDE G6PD

mefloquine= used in chloroquine resistance regions
-psychotic side effects

Question 16

what malaria drug is used as prophylaxis? in who?

Answer 16

mefloquine

pregnant mamas against falciparum/ vivas

Question 17

quinine- moa, tox

Answer 17

• CURE of erythrocytic stages of chloroquine resistant and MDR falciparum
• MOA= inhibits paraisde feeding mech, generates oxidative stress
• tox= cinchonism, stim pancreatic beta cells, hypoTN
• exclude G6PD
• CI in pregnancy

Question 18

whats cinchonism again?

Answer 18

= visual dysfx, tinnitus, n/v

Question 19

what is quinine also/ maybe better known as?

Answer 19

class Ia anti-arhythmic

Question 20

atovaquone + proguanil - use, moa

Answer 20

drug resistance falciparum, PCP pneumonia, babesiosis

atovaquone= blocks ETC of p falciparum

proguanil = inhibits parasitve DHFR, potentiates mitochondiral toxicity of atovaquone

Question 21

artemisinin- use, moa

Answer 21

use: fastest parasite clearance of all antimalarials
- kills blood stages of ALLLLL plasmodium species
- combine with other drugs to prevent resistance

moa= binds iron, breakfs down peroxide bridges –> free radicals