Antiparasites

Question 1

Class, Agent and Mechanism of drug for: -Giardia, Entamoeba, Trichomonas

Answer 1

Class: Nitroimidazoles: Agents: Tinidazole, metronidazole Mechanism: DNA damage, inhibits parasite respiration, toxic radicals

Question 2

Adverse effect of Tinidazole and Metronidazole (nitroimidazole class)

Answer 2

disulfiram like effect with alcohol (makes you feel very hungover)

Question 3

Drug and mechanism for Cryptosporidium

Answer 3

-Nitazoxanide -inhibits parasite electron transport

Question 4

Treatment for cystoisospora belli, formerly Isospora belli

Answer 4

TMP/SMX

Question 5

Luminal roundworms (helminths): name the class, agent, and mechanism

Answer 5

Class: Benzimidazoles Agent: albendazole, mebendazole Mechanism: inhibit worm motility by inhibiting cytoplasmic microtubules, and blocking glucose uptake

Question 6

Name the drug class, agent, mechanism, and effect for ascaris, pinworm, whipworm, hookworm (necator), and strongyloides

Answer 6

Class: Synaptic transmission Agent: pyrantel pamoate Mechanism: nicotinic activation, cholinesterase inhibition Effect: spastic paralysis

Question 7

Diethylcarbamazine (DEC) is used for what kind of parasites?. Explain the mechanism and effect of the drug

Answer 7

-Neglected tropical diseases Mechanism: decreased response to Ach, alter cuticle Effect: flaccid paralysis

Question 8

Ivermectin What is the mechanism and effect? What parasites does it normally treat?

Answer 8

Mechanism: GABA agonist, does not cross BBB Effect: Flaccid paralysis Treats tissue roundworms (strongyloides), and filarial roundworms (onchocerca, wuchereria, brugia, loa)

Question 9

Treatment for tapeworms (Taenia saginata and solium), and flatworms (schistosoma) What’s the drugs mechanism and effect

Answer 9

-Praziquantel Mechanism: increases membrane permeability to Ca2+, vacuolization of cuticle Effect: -tetanic contraction -exposure of parasite antigens and immune recognition, inhibits parasite “masking” note: for cysticercosis in taenia solium, treat with albendazole

Question 10

Quinolines: -primary use/targets -advantages -mechanism

Answer 10

-erythrocytic stage (primaquine also in hepatic stage) -rapidly active -inhibits heme polymerase, which is the enzyme responsible for binding toxic heme to insoluble particles –> toxic heme kills organism think “queens (quins) eat the heme”

Question 11

Really well tolerated antimalarial drug, but has retinal toxicity if given high cumulative dose

Answer 11

Chloroquine

Question 12

Causes ringing of ears, nausea, vomiting (cinchonism), increases QT interval

Answer 12

Quinine

Question 13

Neuropsychiatric side effects with this anti-malarial drug

Answer 13

Mefloquine

Question 14

Need to test for G6PD when prescribing this anti-malarial drug, due to its hemolysis in G6PD deficiency

Answer 14

Primaquine

Question 15

It is moronic to prescribe this drug, due to increasing resistance in P. falciparum

Answer 15

Chloroquine (ok in Central America, Haiti, and China)

Question 16

Atovaquone/proguanil mechanism of action

Answer 16

Electron transport inhibitor

Question 17

Artemisinin derivative (chinese weed) mechanism

Answer 17

Inhibits protein and nucleic acid synthesis

Question 18

Two sites in malaria life cycle primaquine specifically works

Answer 18

-Schizont stage in the liver, and gametocyte sexual form

Question 19

5 major Anti-Malarial classes

Answer 19

1. Quinolines
2. Folate pathway
3. Atovaquone/proguanil
4. Tetracycline
5. Artemisinin derivatives