Treatments of GI Infections

Question 1

IV vancomycin’s claim to fame was treatment of…

Answer 1

MRSA

Question 2

what is the first line treatment for initial, non-severe c. diff infection?

Answer 2

oral vancomycin

Question 3

metronidazole was previously used for c. diff which has since developed resistance, so now we use…

Answer 3

the macrolide fidaxomicin

Question 4

what is the treatment for initial episode, severe c. diff?

Answer 4

oral vancomycin

Question 5

what is the treatment for initial episode c. diff when fulminant?

Answer 5

oral vancomycin + IV metronidazole

Question 6

what is the treatment for the first recurrence of c. diff?

Answer 6

oral vancomycin if metronidazole was used for treatment initially…

…otherwise…

oral fidaxomicin if vancomycin was used for the initial episode

Question 7

name the two agents used for treatment of c. diff

Answer 7

oral vancomycin + metronidazole

STAR

Question 8

name the two agents used for treatment of campylobacter jejuni

Answer 8

ciprofloxacin + azithromycin

STAR

Question 9

name the two agents used for treatment of salmonella spp.

Answer 9

ciprofloxacin + azithromycin

STAR

Question 10

name the two agents used for the treatment of shigella spp.

Answer 10

ciprofloxacin + azithromycin

STAR

Question 11

name the three drugs in the benzimidazoles

Answer 11

1. albendazole
2. mebendazole
3. thiabendazole (cutaneous only)

Question 12

what is the cutaneous only benzimidazole?

Answer 12

thiabendazole

Question 13

name the drug class

MOA:
inhibition microtubule polymerization via beta-tubulin binding
- reduced glucose transport

inhibition mitochondrial fumarate reductase
- resulting in immobilization and death

Answer 13

benzimidazoles

albendazole tends to be treatment of choice

Question 14

name the drug

MOA: selective for glutamate-gated chloride channel, results in paralysis and death of the worm

Answer 14

ivermectin

full description:

• binds selectively, with high affinity, to glutamate-gated chloride ion channels
• induces hyperpolarization –> tonic paralysis of the worm’s nerves/musculature (immobilization and death)

Question 15

ivermectin is used with albendazole for the treatment of…

Answer 15

strongyloides stercoralis

Question 16

name the drug

MOA: interferes with PFOR of ETC

Answer 16

nitazoxanide

full description:
interferes with pyruvate:ferredoxin oxioreductase (PFOR) enzyme-dependent ETC

Question 17

name the drug

MOA: membrane permeability and paralysis

Answer 17

praziquantel

full description:

• increases cell membrane permeability resulting in loss of IC Ca, massive contractions ending in paralysis of musculature
• disintegration of schistosome tegument followed by attachment of phagocytes leading to death

Question 18

name the drug

MOA: depolarizing muscular blocker; can result in spastic paralysis

Answer 18

pyrantel pamoate

full description:

• depolarizing neuromuscular blocker
• opens non-selective cation channels and induces a marked, persistent activation of nicotinic-acetylcholine receptors (stimulates release of acetylcholine)
• shown to inhibit cholinesterases (spastic paralysis of parasite)

Question 19

name the GI focused anti-protozoal agents

Answer 19

1. paromomycin
2. metronidazole
3. tinidazole

Question 20

name the drug

MOA: unknown but works similar to aminoglycosides (30-S)

Answer 20

paromomycin

Question 21

name the drugs

MOA: nitro-radicals disrupt DNA

Answer 21

metronidazole and tinidazole

pro-drugs, activated by electron transfer –> creation of nitro-radicals

Question 22

name the drug

selectively interferes with mitochondrial electron transport and ATP/pyrimidine biosynthesis

Answer 22

atovaquone

Question 23

name the drug

selective inhibition DHFR-TS –> decreased DNA synthesis + depletion of B9

Answer 23

proguanil

full description: selectively inhibits bifunctional dihydrofolate reductase-thymidylate synthetase enzyme of plasmodia resulting in inhibition of DNA synthesis and depletion of folate cofactors

Question 24

atovaquone-proguanil is used to treat…

Answer 24

plasmodium falciparum

Question 25

name the agents of choice for entamoeba histolytica

Answer 25

metronidazole followed by paromomycin

Question 26

name the agent of choice for ancylostoma spp. and necator americanus

Answer 26

albendazole (mebendazole)

hookworm

Question 27

name the agent of choice for ascaris lumbricoides

Answer 27

albendazole (mebendazole)

roundworm

Question 28

name the agents of choice for giardia

Answer 28

metronidzaole (tinidazole)

Question 29

name the agent of choice for adult forms of diphyllobothrium latum and taenia (solium, except for cystericercosis)

Answer 29

praziquantel

tapeworm

Question 30

name the agents of choice for larval form of echinococcus granulosus

Answer 30

albendazole + praziquantel

tapeworm

Question 31

name the agents of choice for larval form of taenia solium (cysticercosis)

Answer 31

albendazole, esp. in brain

tapeworm

Question 32

name the agent of choice for enterobius vermicularis

Answer 32

mebendazole (albendazole)

pinworm

Question 33

name the agents of choice for schistosoma spp

Answer 33

praziquantel + steroids for neurological dz

Question 34

name the agent of choice for strongyloides stercoralis

Answer 34

ivermectin

threadworm

Question 35

name the agents of choice for trichuris trichirua

Answer 35

mebendazole (albendazole)

whipworm

Question 36

name the agents of choice for trichinella

Answer 36

albendazole (mebendazole) + steroids for severe dz

trichiniellosis

Question 37

name the agent of choice for cyrptosporidium spp

Answer 37

nitazoxanide

Question 38

name the agents of choice for cycylospora cayetanensis

what if the patient has sulfa allergies?

Answer 38

TMP-SMZ (has effect on folate synthesis)

ciprofloxacin