Antiprotozoal & Anthelmintic Agents

Question 1

How is Metronidazole (Flagyl) administered?

Answer 1

Oral, IV, Topical

Question 2

What is the MOA for Metronidazole (Flagyl)?

Answer 2

Inhibits DNA synthesis; Reduced by rxn with reduced ferredoxin; Metabolites taken up into DNA

Question 3

What is the spectrum of Metronidazole?

Answer 3

• Anaerobes only
• Bacteriocidal – kills amoeba in tissue (trophozoites)
• Penetrates CSF

Question 4

What are the uses of Metronidazole?

Answer 4

DOC:
E. histolytica (+ luminal amebicide) (symptomatic)
G. lamblia
T. vaginalis

Other: 
B. fragilis
C. diff
Non-specific BV
Rosacea (+ clinda)

Question 5

What are the toxicities of Metronidazole?

Answer 5

• Disulfiram-like rxn
• Dysgeusia (metallic taste)
• GI
• CNS/PNS toxicity (rare)
• Candida superinfection
• Hypersensitivity

Question 6

What is the MOA for Tinidazole?

Answer 6

Similar to Metronidazole

Inhibits DNA synthesis; Reduced by rxn with reduced ferredoxin; Metabolites taken up into DNA

Question 7

What are the uses of Tinidazole?

Answer 7

2nd DOC:
E. histolytica (+ luminal amebicide) (symptomatic)
G. lamblia
T. vaginalis

Used in those who cannot tolerate Metronidazole

Question 8

How is Emetin and Dehydroemetine administered?

Answer 8

SC or IM injection

Question 9

What are the uses for Emetin and Dehydroemetine?

Answer 9

Alternate to metronidazole for
E. histolytica

Limited to unusual circumstances in which metronidazole is not effective (would be unable to use tinidazole as it is a derivative of metronidazole)

Question 10

What are toxicities of Emetin and Dehydroemetine?

Answer 10

• Cardiotoxicity
• Serious GI effects
• Teratogenicity

Question 11

When is Emetin and Dehydroemetine contraindicated?

Answer 11

• Cardiac disease
• Renal disease
• Pregnancy

Question 12

How is Iodoquinol administered?

Answer 12

Oral

Question 13

What are the uses for Iodoquinol?

Answer 13

E. histolytica (asymptomatic)

Luminal trophozoites

Question 14

What are toxicities of Iodoquinol?

Answer 14

• High iodine content (thyroid enlargement, nail/hair/skin/sweat discoloration)
• Optic neuritis/Optic atrophy – can lead to blindness (rare)
• Skin rxn, HA, diarrhea

Question 15

How is Paromomycin administered?

Answer 15

Oral, cream

Question 16

What is the MOA of Paromomycin?

Answer 16

Aminoglycoside

Question 17

What are the uses of Paromomycin?

Answer 17

Asymptomatic E. histolytica (or with metronidazole for symptomatic)

Giardiasis, T. vaginalis

Luminal trophozoites

Question 18

Why are the side effects of Paromomycin not as severe as a typical aminoglycoside?

Answer 18

Not significantly absorbed from GI tract, so do not see typical side effects associated with aminoglycosides

Question 19

What are the uses of Diloxanide furoate?

Answer 19

Luminal trophozoites

Question 20

What needs to be administered with Pyrimethamine + Sulfadiazine and why?

Answer 20

Administer with folinic acid (leucovorin) as pyrimethamine prevents conversion of folic acid

Question 21

What are the uses of Pyrimethamine + Sulfadiazine?

Answer 21

DOC: 
Toxoplasma gondii (Toxoplasmosis)

Question 22

What is the MOA for Trimethoprim + Sulfamethoxazole (Bactrim)?

Answer 22

Inhibition of folate metabolism

Question 23

What are the uses for Trimethoprim + Sulfamethoxazole (Bactrim)?

Answer 23

DOC:
P. jirovecii (Pneumocystis pneumonia)

Prophylaxis against P. jirovecii in AIDS

Toxoplasmosis

Question 24

How is Pentamidine administered?

Answer 24

IM - active disease

Nebulizer - prophylaxis

Question 25

What is the MOA for Pentamidine?

Answer 25

Inhibits DNA replication

Question 26

What are the uses for Pentamidine?

Answer 26

P. jirovecii Reserved for those who cannot tolerate Bactrim

Question 27

What are the toxicities of Pentamidine?

Answer 27

- Hypotension, arrhythmias, hypoglycemia

Question 28

What is the DOC for symptomatic E. histolytica?

Answer 28

Metronidazole + luminal amebicide (diloxanide furoate, iodoquinol, paromomycin)

Question 29

What is the DOC for G. lamblia?

Answer 29

Metronidazole

Question 30

What is the DOC for T. vaginalis?

Answer 30

Metronidazole

Question 31

What is the 2nd DOC for symptomatic E. histolytica?

Answer 31

Tinidazole + luminal amebicide (diloxanide furoate, iodoquinol, paromomycin)

Question 32

What is the DOC for Toxoplasma gondii (Toxoplasmosis)?

Answer 32

Pyrimethamine + Sulfadiazine + folinic acid (leucovorin)

Question 33

What is the DOC for P. jirovecii (Pneumocystis pneumonia)?

Answer 33

Trimethoprim + Sulfamethoxazole (Bactrim) + folinic acid (leucovorin) OR Pentamidine (Pentam) in IM form (if cannot tolerate Bactrim)

Question 34

What is used for prophylaxis against P. jirovecii in AIDS patients?

Answer 34

Trimethoprim + Sulfamethoxazole (Bactrim) OR Pentamidine (Pentam) in nebulizer form (if cannot tolerate Bactrim)

Question 35

What is the MOA for Albendazole and Mebendazole?

Answer 35

Binds to parasite beta-tubulin, inhibiting microtubule polymerization – inhibits the microtubule-dependent uptake of glucose

Question 36

What are the toxicities of Albendazole and Mebendazole?

Answer 36

- May be embryotoxic/teratogenic - Abd discomfort, diarrhea - Monitor liver function with long-term therapy

Question 37

What is the MOA for Pyrantel Pamoate?

Answer 37

Cholinesterase inhibitor; produces depolarizing neuromuscular blockade in worm

Question 38

What is the MOA for Ivermectin?

Answer 38

Paralyzes parasite; intensifies GABA-mediated transmission of signals in peripheral nerves

Question 39

What is the DOC for roundworms/nematodes?

Answer 39

Albendazole or Mebendazole or Pyrantel Pamoate

Question 40

What is the 2nd DOC roundworms/nematodes?

Answer 40

Ivermectin

Question 41

What is the DOC for Flukes/Trematodes?

Answer 41

Praziquantel

Question 42

What is the DOC for Tapeworms/Cestodes?

Answer 42

Praziquantel

Question 43

What is the 2nd DOC for Tapeworms/Cestodes?

Answer 43

Albendazole

Question 44

What is the DOC for asymptomatic E. histolytica?

Answer 44

Luminal amebicide: ``` Iodoquinol (Yodoxin) Paromomycin (Humantin) Diloxanide furoate (Furamide) ```

Question 45

If a patient cannot tolerate Bactrim for their P. jirovecii infection, what should be given instead?

Answer 45

Pentamidine (Pentam)