Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Exam 5 - Therapeutics > Med chem of antimalarial & antiparasitic agents > Flashcards

Med chem of antimalarial & antiparasitic agents Flashcards

1
Q

What is pediculosis?

A

Lice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the organism for head lice?

A

Pediculus humanus capitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where is pediculus humanus capitis mostly found?

A

Head, eyebrows and eyelashes
-They feed on human blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Is pediculus humanus mainly sx or asx?

A

Asymptomatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Most common symptom of pediculus humanus

A

ITCHING
-Allergic rxn to bites
-May take 4-6 weeks for itching to appear
-Scratching can sometimes lead to infection by normal flora

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Life cycle of pediculus humanus

A

-Eggs planted ~1/4 inch from the scalp so that they are close to heat source and blood (on hair behind ears & back of neck)
-Eggs (nits) hatch after 6-9 days (live ~30 days on human head); ~2 days if they fall off bc they cannot feed
-Adults can only crawl, so must have direct contact with source

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Treatments for pediculus humanus

**OTC options

A

-Only kills live lice (so MUST tx twice 9-10d later) –> spinosad is the only exception

OTC options
-Naturally occurring pyrethrins
-Synthetic pyrethroids (for resistant strains)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What should you look for before giving a patient naturally occurring pyrethrins?

A

Ragweed or chrysanthemum allergy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Prescription options for pediculus humanus

A

-Spinosad 0.9% topical suspension (kills nymphs & adults)
-Benzyl alcohol lotion
-Ivermectin lotion
-Malathion lotion (organophosphate insecticide); for > 6 y/o bc more toxic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Spinosad (agonist)

A

-Natural product
-12 member macrolide
-Broad spectrum insecticide
-Nicotinic acetylcholine receptor agonist
-Rapid excitation of the insect nervous system causes death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Perethrins (antagonist)

A

-Piperonyl butoxide synergistically enhances activity
-Rapidly metabolized if absorbed (non-toxic)
-Some inhibitory activity against human cells –> toxicity (would have to have a high concentration for it to be toxic)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Home remedies (vinegar, isopropyl alcohol, mayo, melted butter, etc) _____ work

A

DO NOT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is helminth infection?

A

Worm infection (~25% of the world’s population is infected with 1 at any given time)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Worms have unique biology because they ____

A

-Multiply outside of their definitive host in contrast to other parasites
-Evade the immune system (infections are chronic –> last for the lifetime of the host)

**We don’t understand how they are able to take over the immune system, but once you start to kill them off, then there is a very strong immune response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Effects on human health of helminth infestations

A

-Compromised nutritional status
-Reduced cognitive process
-Tissue reactions
-Intestinal obstruction or rectal prolapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

____ and ___ -aged children tend to have higher burdens of intestinal worms and schistosomes

A

-Pre-school and school-aged children
*Stunted growth
*Diminished physical fitness
*Impaired memory and cognition leading to educational deficits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How to control helminth infestations

A

Drug treatment
Improved sanitation
Health education

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is enterobius?

A

Ring worm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How does someone commonly get STH (soil transmitted helminth)?

A

Walking around barefoot and step on infected soil –> it can be transmitted through the feet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is entorobiasis?

A

-Pinworm infection
*Most common helminthic infection worldwide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Pinworm is most common in….

A

-School-age children (5-10 y/o)
-Institutionalized pts
-Household members of caretakers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Pinworm is transmitted via

A

fecal-oral transmission
*Eggs are ingested; the adult female comes out of the anus at night and lays eggs around the anus –> human scratches and then can reinfect themselves again

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How is entorobiasis diagnosed?

A

Tape test; sit on tape and test for worms that were around the anus

24
Q

Drug therapy for Helminths

A

Benzimidazoles (Mebendazole, Thiabendazole, Albendazole, Triclabendazole)
**Broad spectrum activity

25
Which benzimidazole is useful against GI and tissue infections?
Albendazole
26
Benzimidazole MOA
-Binds tubulin -Inhibits the formation of microtubules **microtubules grow from the "plus" end & shorten at the "minus" end *Benzimidazoles cap the microtubules so it can no longer grow from the "plus" end, but it continues to shorten from the "minus" end. *Inhibits cell division, secretion of parasite molecules, & glucose uptake bc microtubules get too short *Can bind to mammalian tubulin, but bind to helminth tubulin with higher affinity
27
Albendazole therapeutic use
-DOC for pinworms -Variable absorption -Rapidly converted to albendazole sulfoxide (active metabolite) -Also used for cysticercosis, hookworms, ascariasis, trichuriasis, and strongyloidiasis ***SHOULD NOT BE USED IN PREGNANT WOMEN
28
Mebendazole therapeutic use
Pinworms, hookworms, ascariasis, trichuriasis ***SHOULD NOT BE USED IN PREGNANT WOMEN
29
Pyrantel pamoate
-Broad-spectrum anti-helminth -Available OTC -Highly effective for pinworms and ascaris -Highly insoluble (good bc don't want it absorbed since the helminths are in the intestine)
30
Pyrantel pamoate MOA
-Depolarizes neuromuscular blocking agent -Causes a release of ACh & inhibition of cholinesterase -Worms are paralyzed and then expelled
31
Dosing of pyrantel pamoate -ADR
-Ascariasis: one dose -Pinworms: 2 doses 2 weeks apart *ADR are mild and infrequent
32
_____ is the vaccine available for malaria
RTS-S
33
What does the RTS-S vaccine target?
-Targets parasites that are injected by mosquitoes -4 shot regimen beginning at 5 months -30% reduction in severe malaria **'R' is widespread and increasing
34
5 human malaria parasites
1. Plasmodium falciparum (no dormant stage) 2. Pasmodium vivax 3. Plasmodium ovale 4. Plasmodium malariae 5. Plasmodium knowlesi
35
Which 2 malaria parasites are responsible for most infections?
Plasmodium falciparum and plasmodium vivax
36
Life cycle of plasmodium falciparum
1. Infected mosquito injects sporozoites 2. Sporozoites migrate to liver, where they form merozoites 3. Merozoites are released and invade RBC 4. In the RBC, the merozoite becomes a trophozoite 5. Trophozoite multiplies in RBC; released when RBC ruptures & can infect other RBC 6. Some merozoites become gametocytes 7. Another female mosquito may come along and pick up gametocytes from an infected human. The sexual cycle occurs in the mosquito, where sporozoites are formed.
37
Antimalarial drugs -______ kills the liver stage parasites -_______ kills the erythrocytic form -_____ kill sexual stages and blocks transmission which disrupts the cell cycle
-Tissue schizonticides -Blood schizonticides -Gametocytocides **No single drug is active against all stages **Multiple drugs may be necessary
38
Artemisinin MOA
-Must be activated (likely via heme-iron in food vacuole) -Activated artemisinin may form free radicals
39
Artemisinin
-Rapidly acting blood schizonticide -Not active against liver stage!!!! -Short half-life (1-2H) --> does not stick around long enough to get rid of all the parasites -Commonly paired with longer half-life drugs (to eliminate the rest of the parasites in the blood) **Commonly paired with lumefantrine or -quine
40
Artemisinin -Soluble or insoluble -Can only be used ____ -_____ bioavailability -All semisynthetic artemisinins are converted to ______
-Insoluble -Orally -Low -Dihydroartemisinin (active form)
41
Artemisinin resistance
-Mutations in Kelch 13 gene --Delays progress through the life cycle ** Remains in ring stage longer ** Parasite holds out (remains dormant) until Artemisinin concentrations goes down since Artemisinin has such a short half-life
42
4 drugs that are 4-aminoquinolones
1. Quinine 2. Chloroquine 3. Mefloquine 4. Aminoquinoline
43
Hemoglobin metabolism
1. Malaria parasites ingest hemoglobin from host cell 2. Degrade hemoglobin to amino acids & free heme in food vacuole 3. Free heme is toxic 4. Parasite polymerizes heme into hemozoin, which is nontoxic 5. Chloroquine accumulates in food vacuole and inhibits heme polymerization (remains in toxic form)
44
4-substituted quinolones MOA
-Interferes with heme polymerization -Resistance associated with lack of accumulation in food vacuole **Hemozoin is a flat structure which blocks free heme assembly into crystals
45
Chloroquine -Formulated for ___ use -___ absorbed -_____ volume of distribution -_____ is more commonly stocked in US pharmacies *** Same MOA as chloroquine, but has a hydroxyl at the end of the side chain ***More ____ soluble, but both are soluble
Oral Large Hydroxychloroquine *water
46
Chloroquine resistance
-Primarily from mutations in PfCRT1 *Localized to food vacuole *Causes reduced accumulation of chloroquine *No cross-resistance with mefloquine or quinine -Overexpression of PfMDR1
47
Primaquine -Drug of choice for _____ -Metabolized by _____ *Metabolism is required for activity *Mechanism may involve free radicals
LIVER STAGES (targets actively growing & hypnozoites) of P. vivax & P. ovale --> in combo with chloroqine CYP2D6
48
What are hypnozoites?
Dormant cells that want to stay in the liver ==> get rid of these to prevent recurrences
49
Tafenoquine is related to ____ -Same MOA -Same toxicities -Does not seem to be impacted by CYP2D6 polymorphisms -Should be used with _____ ONLY
Primaquine Chloroquine
50
Primaquine MOA
1. Hydroxylation by CYP2D6 2. H2O2 production which is toxic to parasites
51
Primaquine -Well absorbed ______ -High risk of hemolysis in patients with ____ deficiency -Should NOT be used in pregnant women
Orally G6PD
52
C/I to primaquine
Granulocytopenia Concurrent use of other potentially hemolytic drugs or drugs that suppress myeloid cell development
53
Which antibiotics are used as anti-malarial drugs?
Tetracycline Doxycycline Clindamycin **Blood schizonticides
54
Antibiotics target components of ____ -____ acting -_____ commonly paired with quinine or quinidine for tx of falciparum malaria -____ is used for chemoprophylaxis in areas with high resistance to mefloquine
Apicoplast *Plant-like organelle that carries out essential biochemical processes Doxycycline Doxycycline
55
Tetracyclines inhibit ____ by preventing the binding to ____
Protein synthesis Ribosome 50S & blocking tRNA from binding

Exam 5 - Therapeutics (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions