Antiparasitics 2 (LaCount) Flashcards
1
Q
Parasitic infections associated with HIV (U.S. and Global)
A
US = PCP, Toxo, Crypto
Worldwide = Malaria, Leshmania, T. cruzii (Chagas)
2
Q
Pentamidine mechanism
A
unknown
3
Q
Pentamidine’s major problem
A
its highly toxic
50% of patients have sides
4
Q
Pentamidine ROA
A
parenteral
5
Q
Pentamidine Sides
A
hyper/hypoglycemia (rare)
6
Q
Pentamidine is first line for what?
A
West African Trypanosomiasis
**also Alternative treatment for visceral leishmania and Pneumocystosis
7
Q
Anaerobic protozoa
A
- E. Hystolytica
- Giardia
- Trichomonas vaginalis
8
Q
One of the most common water borne illnesses in US
A
giardia
9
Q
Incidence of T. vaginalis in US
A
20-25% of women
10
Q
E. Hystolytica cysts are killed by…
A
boiling, but not by chlorination
11
Q
Amebiasis is more common ________, but…
A
Latin america, Africa, India
but it can occur anywhere
12
Q
Most amebiasises are _____
but…
A
asymptomatic
but some people develop liver abscesses
13
Q
Giardia incidence in developed countries
A
2% adults
7% kids
14
Q
Most common intestinal parasite in US
A
giardia
15
Q
Giardia Tx
A
Metronidazole
Nitazoxanide
16
Q
Cryptosporidium is the most frequent cause of…
A
recreational water-related disease outbreaks
17
Q
Most common Cryptosporidium symptom
A
watery diarrhea
other sx = N/V, cramps, dehydration, weight loss and fever!
18
Q
Drug of choice for Cryptosporidium
A
Nitazoxanide!
19
Q
T. vaginalis Sx
A
vaginitis with purulent discharge
vulvar and cervical lesions
(often asymptomatic in men)
20
Q
Metronidazole is DOC for
A
E. histolytica, Giardiasis, Trichomonas
21
Q
Mzole kills…
A
kills trophozoites, not cysts
22
Q
Mzole mechanism
A
unknown
activated by anaerobe ETC proteins
23
Q
Drug similar to Mzole? How is it different?
A
Tinidazole
lower toxicity
24
Q
Mzole and alcohol may result in…
A
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**
