L15 Antiprotozoals Flashcards by Trent mueller

What protozoa can exist as a trophozoite or dormant cyst, is transmitted by ingestion of cysts in water, food, feces, primarily infects intestinal mucosa causing bloody diarrhea, but can also spread to liver?

Entamoeba histolytica

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Features of Giardia

Protozoan active as a trophozoites or a dormant cyst
Infection route same as E. histolytica, i.e. ingestion of cysts from water, food, feces
Causes gastroenteritis, diarrhea major Sx c loss appetite, hematuria, loose stools, stomach cramps, bloating, gas
Sx appear 1-2 weeks after infection and can cycle
Binds small intestine and blocks nutrient absorbtion
Animals major reservoirs

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What parasite exists in males and females, causes cervicitis, urethritis, vaginitis, yellow-green frothy itchy foul-smelling vaginal discharge, is sexually transmitted and is often asymptomatic in men?

Trichomonas vaginalis

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Why are pregnant women and HIV patients not supposed to clean the litter box?

Domestic animals like cats carry Toxoplasmosis gondii
Mild with flu-like Sx in immune competent
AIDS or pregnant can cause disseminated life-threatening infection

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What is one of the leading causes of death in HIV patients that involves a life-threatening pneumonia?

Pneumocystis jiroveci

Not sure if fungus or protozoan

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What is the DOC for E. histolytica, G. lamblia, T. vaginalis?

Metronidazole (Flagyl)

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What are the uses of Metronidazole (Flagyl)

DOC for E. histolytica, G. lamblia, T. vaginalis
Also used for some anaerobicbacterial infections like that from Bacteroides fragilis and C. difficile
Also used for non-specific bacterial vaginosis or Gardnerella vaginitis

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Which anti-protozoal drug can cause a metallic taste, reddish urine, and disulfiram-like reaction, and must be used c caution in liver disease?

Metronidazole (Flagyl)

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What are the pharmacokinetics of Metronidazole?
Admin route
Metabolism
Where effective
Drug interactions

Oral, but can be IV or topical
Metabolized in liver–can affect drugs like cimetidine, hydantoins, oral anticoagulants, others
Caution in liver disease
Effective in intestines and extra-intestinal

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What drug is similar to Metronidazole, has a long half-life, is better tolerated, and has same coverage? What is the coverage?

Tinidazole (Tindimax)

E. histolytica, G. lamblia, T. vaginalis

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When must you combine a drug with Metronidazole or Tinidazole for effectiveness?

For luminal amoebiasis

Must use a luminal amoebicide like Iodoquinol

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What is Iodoquinol (Yodoxin)?

Luminal amoebicide effective against trophozoites and cysts of E. histolytica
Often combine with Metronidazole

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Which drug is assoc. c high iodine content leading to thyroid enlargement and also can cause serious adverse effects to the eye like optic neuritis and optic atrophy leading to blindness?

Iodoquinol (Yodoxin)

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Paromomycin (Humatin)

Aminoglycoside antibiotic
Oral and cream
Effective for amoebiasis, giardiasis, T. vaginalis (cream)
Effective against luminal trophozoites b/c not well absorbed

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What aminoglycoside antibiotic is useful for amoebiasis, giardiasis, T. vaginalis?

Paromomycin (Humatin)

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Diloxanide Furoate (Furamide)

Luminal trophozoites but not tissue trophozoites like E. histolytica
Combined with metronidazole to treat amoebiasis and asymptomatic carriers
Only available from the CDC

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What drugs can be used to treat asymptomatic amoebiasis?

Iodoquinol (Yodoxin)
Paromomycin (Humatin)
Diloxanide Furoate (Furamide)

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What drugs are combined with metronidazole to treat amoebiasis?

Iodoquinol (Yodoxin)
Paromomycin (Humatin)
Diloxanide Furoate (Furamide)

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What drugs can be given to treat severe intestinal or systemic E. histolytica when metronidazole is not an option? What are the SE?

Emetine and Dehydroemetine (Mebadin)
Parental only
Serious cardiotoxicity, teratogenicity, and GI effects

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Tetracycline use for parasites

Tetracyclines are used to kill the bacteria that E. histolytica and G. lamblia require for life

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What is the treatment of choice for toxoplasmosis?

Pyrimethamine + Sulfadiazine + Folinic acid

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What is the drug of choice for pneumocystosis? What are the other uses of this drug?

TMP-SMX (Bactrim)
Alternate Tx fro toxoplasmosis
Prophylaxis for P. carinii in AIDS
Preferred Tx for P. carinii in kids

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What drugs can be used if TMP-SMX is not an option for pneumocystosis?

Pentamidine (Pentam; Nebupent)
Treats an active infection and nebulizer can be used for prophylaxis
SE: hypotension, arrhythmias, hypoglycemia

Atovaquone (Mepron)

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What kind of organism is cryptosporidium?

Protozoan parasite
Can infect the GI or the lungs
No real treatment

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What is a helminth?

Parasitic worm

What are the 3 major groups of helminths?

Nematodes, cestodes, trematodes

What are nematodes?

Roundworms

Characteristics of Ascaris lumbricoides (roundworm)

Roundworm common in Asia, Africa, Latin America Intestinal parasite Infected by ingesting eggs from soil or water Type of nematode

What helminth lays eggs in perianal area at night? | Other characteristics?

``` Enterobius vermicularis (pinworm) Very common in US in crowded and unsanitary places like daycare centers Intestinal parasite Fecal-oral Type of nematode ```

Characteristics of Necator americanus

``` (Hookworm) Common in tropical areas and southern US Intestinal parasite Infects through the skin, migrates to lungs, up trachea, down to GI Can cause pneumonitis in the lungs Type of nematode ```

``` (Hookworm) Common in tropical areas and southern US Intestinal parasite Infects through the skin, migrates to lungs, up trachea, down to GI Can cause pneumonitis in the lungs ```

Necator americanus | Type of nematode

Characteristics of Strongyloides stercoralis

``` Threadworm Warm climates and southern US Intestinal tract Go through the lungs and back to GI for autoinfection leading to high parasite loads Type of nematode ```

What dog parasite can infect humans but can't fully develop in humans and migrates throughout many tissues causing eosinophilia and necrosis?

Toxicara canis (Visceral larva migrans) Affects lung, brain, liver, muscles, etc Type of nematode

What parasite infects the epidermal/dermal junction and causes inflammation and scarring of the skin? Where does this parasite usually prefer to live?

``` Ancylostoma braziliense (Visceral larva migrans) Adult worm lives in the intestines of dogs Type of nematode ```

What worm is commonly acquired through eating raw or poorly cooked pork?

Trichinella spiralis (Trichinosis) Type of nematode Intestinal parasite of humans, pigs, and others Larvae migrate through intestinal wall into other tissues like skeletal muscle, heart, lungs, etc.

Wuchereria bancrofti

``` Roundworm–Type of nematode Major cause of lymphatic filariasis Central Africa and Nile delta, S and Central America, tropical asia Leads to elephantiasis Spread by mosquitos ```

Loa Loa

Round worm of the eye found in Africa and India | Causes filarial disease

What worm causes river blindness?

Onchocerca volvulus

What are cestodes?

Segmented Tapeworms

What is the beef tapeworm and where in the world is it found?

Taenia saginata Europe, Near East, South America From undercooked beef containing cysticerci

What worm can be picked up from eating raw fish from Japan, Europe, and parts of N and S America?

Diphyllobothrium latum (Fish tapeworm)

What intestinal tapeworm is commonly found in Mexico, Latin America, Africa, SE Asia, Philippines, and can have larvae in the brain and muscle causing cysticercosis? How is this acquired?

Taenia solium | From eating undercooked pork

What are Trematodes or flukes?

Non-segmented flatworms

What are schistosomes?

Blood flukes and hepatic flukes Penetrate skin from contaminated water and go through lymph and blood to liver to mature. Then migrate to vessels of the intestines or bladder as adults Unique worms in that have male and female worms

Schistosoma mansoni

Africa, Mid ast, S America Dysentery and diarrhea Intestinal schistosomiasis Egg has characteristic lateral spine

Schistosoma haematobium

Africa and Mid East Hematuria and dysuria Urinary schistosomiasis

Schistosoma japonicum

Far East Only blood fluke in China and Philippines diarrhea and dysentery Most infectious of schistosomiasis organisms Eggs mostly in stool but can be in urine as well

Normally, laxatives are not used with antihelminthics anymore except for one exception?

Taenia solium | Want to flush out adults before segments can burst with eggs

What drugs are used for Nematodes (roundworms)?

``` Pyrantel Pamoate (Antiminth) Ivermectin (Mectizan) ```

Pyrantel Pamoate (Antiminth)

``` Oral drug for roundworms Broad spectrum Alternative to mebendazole Cholinesterase inhibitor for the worms Not well absorbed so few SE OTC ```

Ivermectin (Mectizan)

``` Oral Rapid absorption and wide tissue distribution Effective against many roundworms Drug of choice for filaria infection Paralyzes roundworm by intensifying GABA ```

What drug is useful for cestodes and trematodes?

Praziquantel (Biltricide)

DOC for all schistosomes First drug for neurocysticercosis Increases worm permeability to Ca leading to contraction and paralysis Well-absorbed so useful for systemic infections

Drug for Trematodes only

Bithionol (Bitin)

For trematodes Uncouples oxidative phosphorylation Oral, well absorbed in GI for systemic infections including liver and lung flukes Only available from the CDC

DOC for entamoeba histolytica

Metronidazole (Flagyl) + luminal amebicide

DOC for giardia lamblia

Metronidazole (Flagyl)

DOC for Trichomonas vaginalis

Metronidazole (Flagyl)

DOC for Toxoplasma gondii

Pyrimethamine (Daraprim) + Sulfadiazine + folinic acid

DOC for Pneumocystis jiroveci

TMP/SMX + folinic acid

``` DOC for roundworms (Nematodes) Ascaris lumbricoides (roundworm) Enterobius vermicularis (pinworm) Necator americanus (hookworm) ```

Pyrantel pamoate (Antiminth)

DOC for tapeworms (cestodes)

Praziquantel (Biltricide)

DOC for flukes (trematodes)

Praziquantel (Biltricide)

What is the only fluke not treated by Praziquantel?

Sheep liver fluke Fasciola hepatica | Use triclabendazole or bithionol instead

L15 Antiprotozoals Flashcards

(64 cards)