2.10 GI Pharm: Parasites + Bugs

Question 1

Reduced by pyruvate:ferredoxin oxidoreductase to active free radicals that attack DNA and other macromolecules in anaerobic organisms?

Answer 1

Metronidazole / Tinidazole

Question 2

Effective against Entamoeba histolytica but could cause a metallics taste in mouth?

Answer 2

Metronidazole / Tinidazole

Question 3

Who should metronidazole and Tinidazole be avoided in?

Answer 3

Disulfiram-like effects (avoid alcohol during and 3 days after treatment).
Avoid in pregnancy and breastfeeding.

Question 4

Aminoglycoside antibiotic interfering with protein synthesis.

Answer 4

Paromomycin

Question 5

Poorly absorbed so good for intestinal infections especially eradication of E. histolytica trophozoites and intestinal carriage?

Answer 5

Paromomycin

Question 6

What drugs are used to treat amebiasis?

Answer 6

Metronidazole, Tinidazole, Paromomycin

Question 7

Interferes with pyruvate:ferredoxin oxidoreductase enzyme-dependent electron transfer in anaerobic metabolism.

Answer 7

NItazoxanide

Question 8

What is effective for Giardia lamblia and cryptosporidium?

Answer 8

Nitazoxanide

Question 9

How is NItazoxanide ADME and ADSE?

Answer 9

Oral (active @ liver = tizoxanide)
GI and CNS side effects

Question 10

Unclear; inhibits oxidative phosphorylation and RNA/DNA synthesis.

Answer 10

Pentamidine

Question 11

Pancreatic toxicity, hypoglycemia, hypotension, renal insufficiency.

Answer 11

Pentamidine

Question 12

Used for Early-stage Trypanosoma brucei gambiense

Answer 12

Pentamidine

Question 13

Pentamidine ADME?

Answer 13

Parenteral; large distribution, minimal CNS penetration, long half-life (~12 days).

Question 14

Inhibits ornithine decarboxylase, blocking polyamine production needed for DNA/RNA synthesis.

Answer 14

Eflornithine

Question 15

IV only; effective for T. brucei gambiense (late stage)

Answer 15

Eflornithine

Question 16

ADSE for Eflornithine?

Answer 16

GI effects, thrombocytopenia, anemia, leukopenia, seizures

Question 17

Produces free radicals, binding to DNA with Oral, rapid absorption; excreted primarily via kidneys

Answer 17

Benznidazole

Question 18

ADSE Benzinidazole ?

Answer 18

Rash (manage with corticosteroids), peripheral neuropathy, rare bone marrow suppression, disulfiram-like effects (avoid alcohol)

Question 19

What is used to treat Trypanosoma cruzi infections (Chagas)?

Answer 19

Benznidazole

Question 20

Inhibits folate metabolism enzymes synergistically (dihydropteroate synthase and DHFR).

Answer 20

TMP-SMX

Question 21

Hypersensitivity, crystalluria, GI effects, megaloblastic anemia in folate-deficient patients.

Answer 21

TMP-SMX

Question 22

Rapid absorption; metabolized in the liver; excreted via urine and used to treat Cyclospora cayetanensis?

Answer 22

TMP-SMX

Question 23

Inhibits dihydrofolate reductase, blocking tetrahydrofolate formation

Answer 23

Pyrimethamine + Sulfadiazine

Question 24

What are the ADSE of Pyrimethamine + Sulfadiazine and who should you not use it for?

Answer 24

Hypersensitivity, megaloblastic anemia, risk in G6PD or folate-deficient patients.

Question 25

Used to treat Toxoplasma gondii and Oral; better tolerated with food.

Answer 25

Pyrimethamine + Sulfadiazine

Question 26

Inhibits protein synthesis (macrolide).

Answer 26

Spiramycin

Question 27

Oral, concentrates in placenta with GI effects, QT prolongation, dermatologic

Answer 27

Spiramycin

Question 28

Spiramycin is used to treat what? (And who?)

Answer 28

Toxoplasmosis in pregnancy

Question 29

Binds glutamate-gated chloride channels, causing paralysis and death

Answer 29

Ivermectin

Question 30

GI upset, rash, dizziness, rare severe reactions due to organism death (e.g., fever, bronchospasm). Avoid in patients taking GABA-enhancing drugs.

Answer 30

Ivermectin

Question 31

What is ivermectin used to treat?

Answer 31

Nematodes and ectoparasites (Onchocerca, Strongyloides, Scabies)

Question 32

Increases Ca²⁺ permeability, causing paralysis and detachment of worms.

Answer 32

Praziquantel

Question 33

Praziquantel ADME and ADSE?

Answer 33

ADME: Oral, well absorbed, metabolized by CYP3A4, excreted via kidneys.
Adverse Effects: GI effects, headache, dizziness, exacerbated symptoms with CNS involvement.

Question 34

What is Praziquantel used to treat?

Answer 34

Trematodes and cestodes (Schistosoma, Taenia)

Question 35

MOA: Inhibits microtubule formation, depleting glycogen stores and reducing ATP production, leading to energy depletion and death

Answer 35

Albendazole / Mebendazole (Benzimidazoles)

Question 36

Albendazole / Mebendazole (Benzimidazoles)
ADME and ADSE?

Answer 36

ADME: Poorly absorbed on an empty stomach; better with fatty meals. Extensive first-pass metabolism.
Adverse Effects: Generally safe; occasional GI effects, headache, dizziness.

Question 37

Uses: Broad-spectrum for nematodes, tissue cestodes, and trematodes?

Answer 37

Albendazole / Mebendazole (Benzimidazoles)

Question 38

Vancomycin MOA?

Answer 38

Inhibits bacterial cell wall synthesis.

Question 39

Used to treat C diff. With minimal ADSE if used orally?

Answer 39

Vancomycin

Question 40

Inhibits RNA polymerase?

Answer 40

Fidaxomicin

Question 41

Used to treat C diff but can cause mild systemic recitations or GI effects?

Answer 41

Fidaxomicin

Question 42

What do you use to treat E.coli cases if you need more than supportive?

Answer 42

fluoroquinolones, azithromycin, or TMP-SMX (severe)

Question 43

What do you use to treat Salmonella, Shigella, Vibrio cholera if supportive care is not enough?

Answer 43

fluoroquinolones, azithromycin, or third-generation cephalosporins**

Question 44

What do you use to treat campylobacter infections?

Answer 44

Azithromycin or fluoroquinolones for severe or prolonged cases.

Question 45

What do you use to treat listeria monocytogenes?

Answer 45

Ampicillin (+ gentamicin = synergy)

Question 46

What do you use to treat yersenia enterocolitica if it is beyond self-limiting illness?

Answer 46

Fluoroquinolones in adults, TMP-SMX in children if needed