Antiparasitic Drugs

Question 1

3 Targets for antiparastic therapy

Answer 1

1-Enzymes or processes found only in the parasite
2-Enzymes/processes found in both host and parasite, but are indispensable only in the parasite
3-Common biochemical functions to both parasite and host, but with different pharmacological properties

Question 2

Metronidazole is used against what?

Answer 2

Giardia, entamoeba, and trichomonas=> anaerobic dwelling protozoans

Question 3

Metronidazole MOA

Answer 3

Prodrug that is reduced by PFOR=> reactive intermediates form wich bind to and disrupt protein and DNA structure/function

Question 4

Metronidazole side effects

Answer 4

headache, dry mouth, metallic taste

Disulfiram-like effect=>avoid alcohol consumption

Question 5

Metronidazole considerations in treating trichomonas

Answer 5

Treat sexual partners simultaneously

Question 6

Metronidazole considerations in tx of amebiasis

Answer 6

Drug of choice for treating symptomatic DZ

Follow this course with more potent luminal amebicide to eradicate non-cyst forms

Question 7

Iodoquinol uses

Answer 7

Effective at eliminating trophozoite and cyst forms of E. histolytica from lumen of intestine

Question 8

Iodoquinol adverse

Answer 8

Gi distrubacnes-take with food to help

Question 9

Paromomycin MOA

Answer 9

aminoglycoside antibiotic
Eliminates both trophozoite and cyst forms of E. histolytica in the lumen of the intestine
NOT active against trophozoites that have invaded tissue

Question 10

C. parvum/ Cryptosporidiosis tx drug

Answer 10

Nitazoxanide=>interferes with PFOR, disrupting anaerobic energy metabolism in parasite

Question 11

Pyrimethamine-Sulfadiazine

Answer 11

Tx of choice for treating toxoplasmosis. Resistance occurs

Question 12

TMP-SMX

Answer 12

Used to treat P. jirovecii infection. Resistance occurs

Question 13

Chloroquine MOA

Answer 13

Unclear, interferes with ability to digest hemoglobin

Question 14

Chloroquine side effects

Answer 14

headache/nausea/vomiting, dizziness, fatigue

Question 15

Chloroquine spectrum

Answer 15

elimates asexual stages of all species of Plasmodium

Question 16

Chloroquine Resistance

Answer 16

Very common via rapid efflux of drug.

When not resistant, very useful

Question 17

Quinone MOA

Answer 17

Localize at digestive vacuoles to interfere with hemoglobin degradation

Question 18

Quinone toxicity

Answer 18

Cinchonism

Hypoglycemia

Question 19

Mefloquine MOA

Answer 19

not know, but well tolerated

Question 20

Mefloquine Toxicity

Answer 20

Some reports demonstrate neuropsychiatric problems to this drug=>hallucinations, delusions, etc.

Question 21

Primaquine MOA

Answer 21

Thought to interfere with mitochondrial ETC=> only drug available that has activity against the liver forms of P. vivax and P. ovale

Question 22

Primaquine toxicity

Answer 22

hemolytic anemia in pts with G6PD=> screen pts for this deficiency before treatment

Question 23

Malarone use

Answer 23

Tx of P. falciparum malaria and as prophylaxis

Question 24

Malarone is a combination of what two drugs

Answer 24

Atovaquone-MOA unknown

Proguanil-Inhibits DHFR

Question 25

Doxycycline MOA

Answer 25

Disrupts protein synthesis in Plasmodium, used for prophylaxis not for treatment

Question 26

Artemisinin Derivatives used in tx of?

Answer 26

P. falciparum infections

Question 27

Benzimidazole drug list

Answer 27

Albendazole, Mebendazole, Thiabendazole

Question 28

Benzimidazole toxicity

Answer 28

Thiabendazole: GI and CNS Albendazole and Mebendazole: Primarily GI Do NOT give them to pregnant pts or children under 2

Question 29

Benzimidazole clinical use

Answer 29

Albendazole and Mebendazole=> ascariasis, pinworm, hookworm, and whipworm Thiabendazole=> second line in tx of strongyloidiasis -Topical preparation in tx of cutaneous larval migrans

Question 30

Ivermectin MOA

Answer 30

Hyperpolarization in muscle cells=>paralysis NO EFFECT on mammalian cells Used in treating intestinal and extraintestinal cells

Question 31

Ivermectin uses

Answer 31

Drug of choice for tx of strongyloidiasis | ALso used in tx of tissue dwelling nematodes including river blindness, eye worm, and filarial worms

Question 32

Pyrantel Pamoate MOA

Answer 32

activates cholinergic nicotnic receptors in teh somatic muscles of nematodes=>paralyzes the parasite. No effect on humans

Question 33

Pyrantel Pamoate uses

Answer 33

Drug of choice for tx of pinworm=> treat the entire household

Question 34

Praziquantel MOA

Answer 34

increases Ca2+ permeability of worm's tegument, causing depolariztion=>increased immune detection

Question 35

Praziquantel uses

Answer 35

Drug of choice for treating nearly all infections caused by tapeworms and flukes

Question 36

Praziquantel dosage

Answer 36

Flukes: Three doses in a single day Tapeworms: A single dose Cysticercosis: two weeks treatment