Antiparasitics 2 (LaCount) Flashcards Preview

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Flashcards in Antiparasitics 2 (LaCount) Deck (85):
1

Parasitic infections associated with HIV  (U.S. and Global)

US = PCP, Toxo, Crypto

 

Worldwide = Malaria, Leshmania, T. cruzii (Chagas)

2

Pentamidine mechanism

unknown

3

Pentamidine's major problem

its highly toxic

50% of patients have sides

4

Pentamidine ROA

parenteral

5

Pentamidine Sides

hyper/hypoglycemia (rare)

6

Pentamidine is first line for what?

West African Trypanosomiasis

 

**also Alternative treatment for visceral leishmania and Pneumocystosis

7

Anaerobic protozoa

  • E. Hystolytica
  • Giardia
  • Trichomonas vaginalis

8

One of the most common water borne illnesses in US

giardia

9

Incidence of T. vaginalis in US

20-25% of women

10

E. Hystolytica cysts are killed by...

boiling, but not by chlorination

11

Amebiasis is more common ________, but...

Latin america, Africa, India

 

but it can occur anywhere

12

Most amebiasises are _____

 

but...

asymptomatic

 

but some people develop liver abscesses

13

Giardia incidence in developed countries

2% adults

7% kids

14

Most common intestinal parasite in US

giardia

15

Giardia Tx

Metronidazole

Nitazoxanide

16

Cryptosporidium is the most frequent cause of...

recreational water-related disease outbreaks

17

Most common Cryptosporidium symptom

watery diarrhea

 

other sx = N/V, cramps, dehydration, weight loss and fever!

18

Drug of choice for Cryptosporidium 

Nitazoxanide!

19

T. vaginalis Sx

vaginitis with purulent discharge

vulvar and cervical lesions

 

(often asymptomatic in men)

20

Metronidazole is DOC for 

E. histolytica, Giardiasis, Trichomonas

 

21

Mzole kills...

kills trophozoites, not cysts

22

Mzole mechanism

unknown

activated by anaerobe ETC proteins

23

Drug similar to Mzole? How is it different?

Tinidazole

lower toxicity

24

Mzole and alcohol may result in...

Antabuse effect

=  N/V, Tachycardia

 

Mzole blocks ACETALDEHYDE DEHYDROGENASE

25

amebiasis treatment - drugs for intestinal forms

Paromomycin + Iodoquinol

26

Paromomycin catergory

distribution

also effective against...

Aminoglycoside

not significantly absorbed in GI

also effective against Cryptosporidium

27

Iodoquinol is an alternative to ____

commonly used in combo with _____

Mechanism?

Alt to Paromomycin

Combo wiht Mzole

Mechanism unknown

28

Nitazoxanide PK

Mechanism

inhibits what organisms?

Rapid metabolism to tizoxanide

Interferes with PFOR (pyruvate ferredoxin oxidoreductase)-dependent electron transport reaction ---> inhibits anaerobic metabolism

 

Inhibits: Sporozoites + Oocysts of Cryptosporidium parvum

Trophozoites of Giardia

29

95% of trypanosomiasis due to what?

brucei gambiense -- west african trypanosomiasis

30

5% of trypanosomiasis caused by ...

brucei rhodesiense -- east african trypanosomiasis

31

Chagas disease caused by

trypanosoma cruzii

32

Trypanosome unique features

Unique organelles - kinetoplast, glycosome

Distinct mech's of gene expression

33

Leshmaniasis drugs

Sodium Stibogluconate

Amphotericin B

34

Alternative meds for leshmaniasis

pentamidine or MILTEFOSINE

35

African trypanosomiasis drugs

Early stage

  • Pentamidine (West)
  • Suramin (East)

Late stage

  • Melarsoprol (E/W)
  • Eflornithine (West)

36

American trypanosomiasis drugs

Nifurtimox

Benznidazole

37

Miltefosine is a ____ analog

Approved for use against ______ in india

Phospholipid

Visceral leishmaniasis

38

Why would one avoid Miltefosine?

It is teratogenic

(avoid if pregnant)

39

Most commonly used drugs for T. cruzi

Nifurtimox and Benznidazole

40

Nifurtimox and Benznidazole mechanism

Activated by a NADH-dependent nitroreductase (mitochondrial)

= generation of nitro radical ions

41

Benznidazole is preferred to nifurtomix because...

it is less toxic

42

N + B reduce _______ of T. Cruzi

BUT they do not...

reduce the severity of the acute phase of T. Cruzi

 

...does not reverse the tissue damage caused by chronic infections

43

With N + B treatment, ____ is common. over the course of treatment, which is about ________ in duration

toxicity

3-4 months

44

Worms have a unique biology in that they... (2)

  • multiply outside of their definitive host
  • Evade the immune system (lifetime chronic infections)

45

Helminths include what catergories

Cestodes (tapeworms)

Trematodes (flukes)

Nematodes (Roundworms)

46

Echinococcosis

  • aka
  • forms what?
  • treatment

Dog tapeworm

forms hydatid cysts in the liver

Albendazole and surgical excision of cysts

47

Cystercercosis

  • caused by
  • produces
  • Tx

  • caused by Taenia solium
  • produces cysterci in the brain and eyes
  • praziquantel, albendazole, surgery

48

Taeniasis

  • caused by (aka)
  • produces
  • Dx and Tx

T. saginata (beef tapeworm)

does NOT produce cysterci

Dx by proglottids in stool, Tx: Niclosamide

49

Diphyllobothriasis

caused by/aka

Dx/Tx

Caused by D. latum (fish tapeworm)

Stool eggs, Tx = Niclosamide

50

Taenia solium causes what two syndromes

Taeniasis (intestinal infection, stool/niclosamide)

Cystercercosis (brain infection, prazi/albend)

51

Which form of Taenia saginata/solium penetrate the intestinal wall and circulate to musculature

Oncosphere

52

Cysticercosis 4 steps

  1. ingestion
  2. oncospheres hatch in intestine
  3. oncospheres invade intestinal wall and migrate to striated muscle, brain, liver
  4. develop into cysticerci

53

Pinworm disease

  • organism
  • hosts
  • Dx and Tx

Enterobiasis

  • Ent. vermicularis
  • humans only host
  • perianal egg ID, Mebendazole or Pyrantel pamoate

 

54

Roundworm disease

  • Organism
  • type of infection
  • Dx
  • treatment

Ascariasis

  • Ascaris lumbricoides (most prevalent multicellular parasite)
  • Intestinal growth of larvae
  • stool egg ID
  • Mebendazole or pyrantel pamoate

55

Threadworm disease

  • organism
  • disease/infection characteristics
  • transmission
  • Dx and Tx

Strongyloidiasis

  • Strongyloides stercoralis
  • Usually benign, can be fatal in ICP due to CNS/organ infctn (HYPERINFECTION SYND)
  • Stool larvae, Tx = Thiabendazole, albendazole, ivermectin

56

Hookworm disease

  • organism
  • transmission
  • Dx and Tx

  • Ancylostoma duodenale and Necator americanus
  • direct penetration of the skin
  • eggs in stool, pyrantel pamoate or mebendazole

57

Whipworm disease

  • Organism
  • Sx
  • Transmission
  • Tx

  • trichuris trichiura
  • N/D, rectal prolapse
  • ingestion of contaminated soil
  • Mebendazole

58

River blindness

  • organism
  • features/Sx
  • Transmission
  • Dx
  • Tx

  • Onchocerciasis (volvulus)
  • SubQ nodules, ocular lesions
  • blackfly bite
  • Detect microfiliariae in skin
  • Ivermectin or surgery

59

Visceral larva migrans

  • organism
  • only ___ cause disease
  • Dx
  • Tx

Toxocara canis

only larvae cause disease

ID larvae in tissue

Mebendazole / thiabendazole

60

Filariasis

  • organism
  • Sx
  • Transmission
  • Dx/Tx

  • Wuchereria bancrofti
  • elephantiasis
  • Anopheles or Culex mosquitoes
  • ID microfilariae in blood, Combo of DIETHYLCARBAMAZINE and ALBENDAZOLE

61

Disease from loa loa

Loiasis

Larvae under skin, leave track marks

worms visible in subconjunctival space

Treated with diethylcarbamazine

62

Dracunculiasis caused by...

drinking water containing intermediate host copepods where larvae live

 

...have to actually remove the subQ worms via surgery

63

Trichinella spiralis diagnosis

muscle biopsy that shows coiled encysted larvae

64

Benzimidazole drugs (3, one fact each)

Mebendazole (1st)

Thiabendazole (Toxicity limits use)

Albendazole (for GI and Tissue)

65

Bendimidazole MOA

binds to tubulin ->> inhibits formation of MT at the PLUS end (minus end still shortens)

Doesn't bind to mammalian tubulin

66

Albendazole DOC for 

Cysticercosis

67

Albendazole rapidly converted to ______

albendazole sulfoxide

 

(active metabolite)

68

Mebendazole used for..

pinworm, hookwarm, ascariasis, thricuriasis

69

Thiabendazole is not preferred b/c...

toxicity and potential teratogen

70

Praziquantel is effective against what catergories of organisms

cestodes and trematodes

 

NO effect on nematodes

71

Praziquantel MOA (lower concentrations)

increased muscular activity at lower [C]

Worms detach from blood vessel walls

migrate from mesenteric vv. -> liver

 

72

Praziquantel higher concentration MOA

tegumental damage

exposes a number of tegumentsl antigens

 

**may also disrupt CALCIUM homeostasis**

73

Prazi is the DOC for..

Dosing?

all forms of schistosomiasis

 

high cure rate with 2-3 doses

--> single dose kills 100% of T. saginata/solium, and D. latum

74

Toxicity for prazi:

more severe reaction to dying worms

75

Ivermectin is DOC for 

strongyloidiasis and onchocerciasis

76

Ivermectin drug type

semisynthetic macrocyclic lactone

77

Ivermectin MOA

Paralyzes microfilariae

Binds to Glutamate-activated Chloride channels in nematode nerve/muscle cells

causes hyperpolarization by increaseing internal [Cl-]

 

*also binds to GABA-gated and ligand gated chloride channels

78

ivermectin doesnt kill...

adult worms

 

(only paralyzes)

79

Ivermectin used to treat _____

onchocerciasis

 

also for ascaris, enteroboius, strongyloides, filariasis

80

Treatment with ivermectin must be continued...

for the lifespan fo the adult worm

81

Pyrantel pamoate is a...

MOA?

What does it treat? (and dosing?)

...broad spec antihelminth (OTC)

MOA = Causes Ach release and inhibits cholinesterase 

 

Tx for pinworms (moderate against hookworms)

  • Ascariasis = one dose
  • Pinworms = 2 doses 2 weeks apart

82

Scabies organism

sarcoptes scabiei

83

scabies burrow in what tissue

stratum corneum of the skin

 

causes itching and rash

84

Treatment for scabies

Permethrin cream

 

(salycylic acid if crusted scabies)

85

Head live tx

Permethrin or pyrethrin

1st application 10 minutes, second application 10 days later

 

Malathion if chronic

Newer pediculicides contain benzyl alcohol, dimethicone, or spinosad