Exam 9: Antihelminthic and Antiprotozoal Drugs

Question 1

Name 3 antihelminthic drugs?

Answer 1

1. Albendazole
2. Pyrantel
3. Praziquantel

Question 2

Name 4 antiprotozoal drugs?

Answer 2

1. Metronidazole
2. Iodoquinol
3. Paromomycin
4. Nitazoxanide

Question 3

What are 2 drugs used to treat pinworm (Enteriobius vermicularis)?

Answer 3

1. Albendazole

2. Pyrantel

Question 4

What are 2 considerations when treating pinworm?

Answer 4

1. treatment works well when the patients adheres to strict personal hygiene standards
2. Treat both the patient and their family members
   (Remember, treat with Albendazole and Pyrantel)

Question 5

What drug is used to treat asymptomatic or mild Ascariasis? Severe?

Answer 5

Mild/Asymptomatic: Albendazole

Severe: Pyarntel pamoate

Question 6

What drug is used to treat Necator americans (hookworm)?

Answer 6

Albendazole

Question 7

What drug is used to treat Taenia solium and saginata?

Answer 7

Praziquantel

Question 8

What is an adjunctive therapy you can use when treating Taenia solium with Praziquantel?

Answer 8

Treatment can result in release of embryos from eggs and result in cysticercosis, so you may want to treat with a purgative (laxative) like Magnesium sulfate.

Question 9

What 2 antihelminthic drugs are used to treat Neurocysticercosis?

Answer 9

Albendazole and Praziquantel

Question 10

What non-antihelminthic drug is used in the treatment of Neurocysticercosis?

Answer 10

Dexamethasone

give it 1-2 days before treatment and 4-7 days after treatment ends.

Question 11

What is a pharmacokinetic consideration with Albendazole?

Answer 11

It has to be metabolized in the liver to Albendazole sulfoxide to be active.

Question 12

What is the mechanism of Albendazole?

Answer 12

Binds to Beta-tubulin, causing inhibition of microtubule polymerization and therefore a decrease in microtubule-dependent glucose uptake by the parasite.

Question 13

Why is Albendazole selective against helminths?

Answer 13

It does not bind well to mammalian Beta-tubulin

Question 14

What are adverse effects of Albendazole?

Answer 14

GI stuff (most frequent)
Teratogenic
Hepatotoxicity/Increased liver enzymes
Leukopenia (perform blood counts every 2 weeks)

Question 15

What is the mechanism of Pyrantel?

Answer 15

Activation of cholinergic nicotinic receptors in nematode muscles, causing a depolarizing neuromuscular blockade (human receptors are different, so it doesnt have this effect)

Question 16

What are adverse effects of Pyrantel?

Answer 16

GI problems (most frequent)
Headache, dizziness, drowsiness
Use with caution in patients with liver failure, pregnant women, and kids under 2.

Question 17

What is the mechanism of praziquantel?

Answer 17

Causes an increase in Ca+ influx, inducing muscle contracture and paralysis, dislodging the suckers
(Little effect on human muscle)

Question 18

What are two types of bugs that Praziquantel can be used for?

Answer 18

Schistosomes (trematodes)

Tapeworms (cestodes)

Question 19

Adverse effects of Praziquantel?

Answer 19

Dizziness, drowsiness, headache, AMS (most common)
GI problems
Increased liver enzymes
Low grade constitutional symptoms several days after therapy.
Avoid in pregnancy (caused abortions in rats)

Question 20

Where can intestinal Entamoeba infections spread and cause?

Answer 20

Liver, abscesses

Question 21

What 2 drugs are used to treat asymptomatic carriers of Entamoeba histolytica?

Answer 21

Iodoquindol and Paromomycin

Question 22

What drug is used to treat symptomatic Entamoeba infections?

Answer 22

Metronidazole, followed by Iodoquinol or Paromycin

Question 23

What 2 drugs are preferred for Giardiasis?

Answer 23

Metronidazole and Nitazoxanide

Question 24

Who gets treated with Trichomoniasis?

Answer 24

Infected woman and her sexual partner(s) to prevent recurrence

Question 25

What drug is used to treat Trichomoniasis?

Answer 25

Metronidazole

Question 26

What two drugs are used to treat Cryptosporidium?

Answer 26

Paromomycin and Nitazoxamide

Question 27

What is the mechanism of Metronidazole?

Answer 27

Inhibits DNA synthesis

Nitro group gets reduced, binds to intracellular macromolecules like DNA, inhibits DNA synthesis.

Question 28

Adverse effects of Metronidazole?

Answer 28

Disulfiram-like reaction with alcohol
Nausea, headache, metallic taste
Carcinogenic in first trimester

Question 29

Where is Iodoquinol effective?

Answer 29

GI tract, because it’s not well absorbed.

Question 30

Adverse effects of Iodoquinol?

Answer 30

Neurotoxicity (optic neuritis, loss of vision)

GI upset

Question 31

Where is Paromomycin effective?

Answer 31

GI tract, because it’s not well absorbed.

Question 32

What is the mechanism of Paromomycin?

Answer 32

It is an aminoglycoside

Binds to the 30S ribosomal, inhibiting protein synthesis

Question 33

What are adverse effects of Paromomycin?

Answer 33

Ototoxicity, nephrotoxicity (aminoglycoside)

Go side effects

Question 34

What is a pharmacokinetic consideration of Nitazoxanide?

Answer 34

Must be hydrolyzed into an active form (tizoxanide)

Question 35

What is the mechanism of Nitazoxanide?

Answer 35

Inhibits pyruvate:ferredoxin 2-oxidoreductase enzyme dependent electron transport reaction
Interfering with anaerobic energy metabolism

Question 36

What are uses of Nitazoxanide?

Answer 36

Diarrhea caused by Cryptosporidium in immunocompetent children 1-11, adolescents, and adults.

Question 37

What is an advantage of Nitazoxanide over Metronidazole?

Answer 37

Doesnt have mutagenic/carcinogenic effects