Pharmacology of GI Infections (Segars) Flashcards by Staci Thomas

What are the bacteria being discussed for treatment in this lecture?

- Clostridioides (Clostridium) difficile
- Campylobacter jejuni
- Salmonella spp.
- Shigella spp.

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What are the treatments used for C. diff?

- Oral Vancomycin (treatment of choice)

- - Fidaxomicin

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What is used for C. diff if it is more severe and the patient clinically presents with hypotension or shock, ileum, and megacolon?

Combination of Vancomycin (oral) and Metronidazole

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What are the treatments for Campylobacter jejuni, Salmonella spp., and Shigella spp. (all the same)?

- Ciprofloxacin (treatment of choice)

- - Azithromycin

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What type of antibiotic is Vancomycin?

Glycopeptide

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What type of antibiotic is Ciprofloxacin?

Fluoroquinolone

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What type of antibiotics are Fidaxomicin and Azithromycin?

Macrolides

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Anthelmintic Agents are divided into a _________ group and miscellaneous group.

Benzimidazole (BZA)

***Common ending is -bendazole!

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What drugs are in the Benzimidazole group of Anthelmintic Agents?

- Albendazole (treatment of choice)
- Mebendazole
- Thiabendazole

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What drugs are in the Miscellaneous group of Anthelmintic Agents?

- Ivermectin
- Nitazoxanide
- Praziquantel
- Pyrantel pamoate

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This Benzimidazole is used cutaneously only due to its high toxicity.

Thiabendazole

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What is the mechanism of action for BZAs?

– Inhibition of microtubule polymerization via beta-tubulin binding, causing reduced glucose transport.

– Inhibition of mitochondrial fumarate reductase, resulting in immobilization and death.

***These things occur to the parasite!

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What is the mechanism of action for Ivermectin?

– Binds selectively, and with high affinity, to Glutamate-Gated Chloride ion channels.

– Induces a hyperpolarization resulting in a tonic paralysis of the worms’ nerves and musculature, resulting in immobilization and death.

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What is an example of what Ivermectin is used for?

Strongyloides stercoralis

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Ivermectin is used with _________ for lymphatic filariasis.

Albendazole

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What is the mechanism of action for Nitazoxanide?

Interferes with PFOR (pyruvate:ferredoxin oxidoreductase) enzyme-dependent electron transfer reaction. This is essential to anaerobic energy metabolism.

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What are examples of use for Nitazoxanide?

- Cryptosporidium pavum
- Giardia labmlia
- Entamoeba histolytica

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What is the mechanism of action for Praziquantel?

– Increases cell membrane permeability resulting in loss of intracellular calcium, causing massive contractions ending in paralysis of musculature.

– Disintegration of schistosome tegument followed by attachment of phagocytes leading to death.

What are examples of use for Praziquantel?

- Schistosoma spp.
- Echinococcus granulosus
- Taenia spp.
- Diphyllobothrium latum

What is the only helminth that has to be used in combination with Albendazole when treated with Praziquantel?

Echinococcus granulosus

What is the mechanism of action for Pyrantel pamoate?

– A depolarizing neuromuscular blocker.

– Opens non-selective cation channels and induces a marked, persistent activation of nicotinic-ACh receptors which stimulates release of ACh.

– Inhibits cholinesterase’s, resulting in spastic paralysis of the parasite.

What are examples of use for Pyrantel pamoate?

- Enterobius vermicularis
- Ascaris lumbricoides
- Ancylostoma spp.
- Trichinella spiralis (adult form ONLY)

What are the GI focused anti-protozoal agents?

- Paromomycin
- Metronidazole
- Tinidazole

Paromomycin is from the _________ family of antibiotics.

Aminoglycoside

What is the mechanism of action for Paromomycin?

Exact mechanism for protozoa unknown, but known to work similar to other aminoglycosides (30-S)

What are examples of use for Paromomycin?

- - Entamoeba histolytica - - Diphyllobothrium latum - - Echinococcus granulosus - - Taenia spp. - - Schistosoma spp.

These drugs have antibacterial and anti-protozoal activity.

- - Metronidazole | - - Tinidazole

What is the mechanism of action for Metronidazole and Tinidazole?

Believed to serve as a pro-drug, activated by electron transfer process creating nitro-radicals which disrupts DNA, killing the organism.

What are examples of use for Metronidazole and Tinidazole?

- - Entamoeba histolytica - - Giardia lamblia - - Costridioides (Clostridium) difficile

Atovaquone-Proguanil are drugs taken together (called Malarone). What are their mechanisms of action?

Atovaquone = Selectively interferes with mitochondrial electron transport and ATP/pyrimidine biosynthesis Proguanil = Selectively inhibits bifunctional dihydrofolate reductase-thymidylate synthetase enzyme of plasmodia resulting in inhibition of DNA synthesis and depletion of folate cofactors.

What are examples of use for Atovaquone-Proguanil?

Plasmodium falciparum

For Amebiasis, what organism would be the cause and how would we treat it?

Entamoeba histolytica Treat with Metronidazole followed by a continued therapy of Paromomycin

For Hookworm, what organism would be the cause and how would we treat it?

Ancylostoma spp. Necator americanus Treat with Albendazole (can also use Mebendazole)

For Roundworm, what organism would be the cause and how would we treat it?

Ascaris lumbricoides Treat with Albendazole (can also use Mebendazole)

For Giardiasis, what organism would be the cause how would we treat it?

Giardia spp. Treat with Metronidazole (can also use Tinidazole)

For Tapeworms in Adult form, what organism would be the cause and how would we treat it?

Diphyllobothrium latum Taenia spp. (including T. solium, except cysticercosis specific) Treat with Praziquantel

For Tapeworms in Larval forms, what organism would be the cause and how would we treat it?

Echinococcus granulosus -- treat with Albendazole + Praziquantel Taenia solium (Cysticercosis) -- treat with Albendazole

For Pinworms, what organism would be the cause and how would we treat it?

Enterobius vermicularis Treat with Mebendazole (can also use Albendazole)

For Schistosomiasis, what organism would be the cause and how would we treat it?

Schistosoma spp. Treat with Praziquantel (+ steroids for neurological disease)

For Threadworms, what organism would be the cause and how would we treat it?

Strongyloides stercoralis Treat with Ivermectin

For Whipworms, what organism would be the cause and how would we treat it?

Trichuris trichiura Treat with Mebendazole (can also use Albendazole)

For Trichinellosis, what organism would be the cause and how would we treat it?

Trichinella spp. Treat with Albendazole (can also use Mebendazole) (+ steroids for severe disease)

What is the treatment for Cryptosporidium spp.?

Nitazoxanide

What is the treatment for Cyclospora cayetanensis?

Trimethoprim-Sulfamethoxazole (TMP-SMZ), but if patient is sulfa-allergic then use Ciprofloxacin