Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Pharmacology > Antiparasitics > Flashcards

Antiparasitics Flashcards

(57 cards)

Start Studying
1
Q

Antiparasitic Drugs - General

A

No vaccines
Commercial incentives limited for many parasitic infections
Parasites often have unique systems that can provide selective targets
Resistance is always a problem

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

Neglected Parasitic Infections in the US

A 
Trypanosoma cruzi (Chagas Disease)
Taenia solium (cysticercosis and neurocysticercosis)
Toxocara (Dog and cat roundworms)
Toxoplasma gondii (TOrches)
Trichomonas (STD)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Parasitic infections associated with HIV

A

In US: Pneumocystis jirovecii, Toxoplasma gondii, Cryptosporidium

Globally: Malaria, Leishmania, Trypanosoma cruzi

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

What are the 5 human malaria parasites?

A 
P. falciparum - constant - all RBCs
P. vivax - 48 hr - hypnozoites in liver
P. ovale - 48 hr - relapsing
P. malariae
P. knowlesi - 24 hr - zoonotic infections
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Malaria parasite life cycle

A

sporozoites injected by mosquito –> go to liver –> merozoites formed (hypnozoites in vivax and ovale) –> merozoites invade and divide and rupture RBCs –> sexual stages produce gametocytes –> gametocytes taken up by mosquito

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

True or False: No drug kills malarial sporozoites.

A

True

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

Malarial drugs that attack LIVER stages (exoerythrocytic schizonticides)

A

Primaquine - merozoties and hypnozoites

Atovaquone and Artemisinins - merozoites

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

Malarial drugs that attack BLOOD stages (erythrocytic schizonticides)

A 
Chloroquine
Mefloquine
Artemisinins 
Quinine
Doxycycline & tetracycline
Clindamycin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Malarial chemoprophylaxis

A

Prevention: insect repellant, insecticides, bed nets

Awareness

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

Drugs for PREVENTION of Clinical Disease

A 
Chloroquine [Aralen] 
Hydroxychloroquine sulfate [Plaquenil]
Atovaquone + Proguanil [Malarone]
Mefloquine [Lariam]
Primaquine 
Doxycycline
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Chloroquine [Aralen]

A

start 1-2 wk prior

continue 4 wk after

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

Hydroxychloroquine sulfate [Plaquenil]

A

start 1-2wk prior

contine 4wk after

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

Atovaquone + Proguanil [Malarone]

A

used in all areas
start 1-2d prior
continue 7 days after

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

Mefloquine [Lariam]

A

start >2wk early
continue 4wk
TOXIC SIDE EFFECTS

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

Primaquine

A

mainly for P. vivax
start 1-2d prior
continue 7 d after

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

Doxycycline

A

used in all areas
start 1-2d prior
continue 4 wk

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

Tx for uncomplicated malaria or unidentified species

A

Chloroquine sensitive: Chloroquine, Hydroxychloroquine sulfate

Chloroquine resistant:
Atovaquone + Proguanil [Malarone]
Artemether + lumefantrine [Coartem] (NOT READILY AVAILABLE)
Quinine sulfate + Doxycycline or Tetracycline or Clindamycin
Mefloquine [Lariam]

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

Tx for uncomplicated malaria: P. vivax or P. ovale

A

CQ sensitive:
Chloroquine
Hydroxychloroquine sulfate + primaquine

CQ resistant (2 drug minimum):
Quinine sulfate + doxycycline
Tetracycline + primaquine 
Atovaquone + Proguanil + primaquine
Mefloquine + primaquine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Tx for uncomplicated malaria: P. malariae or P. knowlesi

A

Chloroquine

Hydroxychloroquine sulfate

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

Sx for complicated malaria

A

Sx: impaired consciousness/coma, severe normocytic anemia, renal failure, pulmonary edema, etc.

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

Tx for complicated malaria

A

IV Quinidine gluconate + doxycycline or tetracycline or clindamycin
[consult cardiologist and experienced physician
monitor: BP, cardiac function, glucose levels (hypotension, widening QRS and/or lengthening QTc interval, hypoglycemia)]

IV Artesunate followed by Malarone, Doxycycline, Mefloquine (if Quinidine gluconate doesn’t work)

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

Artemisinin

A

Derived from Chinese wormwood (Artemesia)
Endoperoxide active group
RAPIDLY acting blood schizonticide
No effect on liver stages
active against all species
short half-life
high recrudescence rate after short course
commonly paired with other drugs (ex. mefloquine or lumefantrine)

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

Artemisinin combination therapy

Study These Flashcards
A

Artemisinin provides rapid knockdown
Longer half-life component eliminates remaining parasites

Combinations:
Artemether + lumefantrin (Coartem)
Artesunate + mefloquine
Dihydroartemesinin + piperaquine

24
Q

Artemisinin antimalarial effect is associated with _____

Study These Flashcards
A

Cmax

concentration dependent killing

25
Artemisinin derivatives
Artemisinin (insoluble - oral) Artesunate (water-soluble - oral, IV, IM, rectal) Dihydroartemisinin (soluble - oral) Artemether (lipid-soluble - oral, IM, rectal)
26
Artemisinin adverse effects
well tolerated nausea, vomiting, diarrhea, and dizziness EMBRYOTOXIC
27
Examples of 4-aminoquinilones
quinine, chloroquine, mefloquine, aminoquinoline Block the polymerization of heme
28
Hemoglobin metabolism
Malaria parasites ingest hemoglobin from host cell --> hemoglobin is degraded into amino acids and free heme(toxic) --> parasite polymerize heme into hemozoin(nontoxic)
29
How does chloroquine effect parasite hemoglobin metabolism
chloroquine accumulates in food vacuole and inhibits heme polymerization (heme(toxic) --> hemozoin(nontoxic))
30
Chloroquine (CQ)
drug of choice for Tx and prophylaxis oral use, well absorbed, large Vd half life 3-5d (terminal half-life 1-2mo)
31
CQ antimalarial effect is associated with _____
T > MIC | opposite of Artemisinin
32
How did CQ resistance occur
developed in at least 2 foci in P. falciparum 1. mutations in PfCRT1 (caused reduced accumulation of CQ) 2. over-expression of PfMDR1 (drug transporter) P.vivax developed resistance later under a different mechanism
33
Adverse effects of CQ
Usually "very well tolerated" Pruritus is common (esp in Africans) Not recommended in IV CONTRADICTED in psoriasis, porphyria, retinal abnormalities, and myopathy Antidiarrheal agents KAOLIN AND CALCIUM interfere with CQ absorption
34
What are some other CQ related compounds
``` Mefloquine Lumefantrine Piperaquine Amodiaquine Halofantrine Tafenoquine ```
35
What substance contains quinine
tonic water
36
Quinine and Quinidine
rapidly acting blood schizonticide active against all Plasmodium and Babesiosis Mode of Action similar to CQ IV for severe falciparum malaria oral for uncomplicated " " Metabolized by CYP3A4 (can raise levels of warfarin and digoxin; also interact with HIV drugs)
37
Adverse effects of Quinine
``` Cinchonism: tinnitus, headache, nausea, dizziness, flushing, and visual disturbances Cardiotoxicity Stimulates uterine contractions Hemolysis Severe hypotension with rapid infusion ```
38
Mefloquine [Lariam] Usage
Resistance increasing Both prophylaxis and Tx Erythrocytic forms - falciparum & vivax
39
Adverse effects of Mefloquine
Neuropsychiatric toxicity: seizures, toxic psychosis, and sleep disturbance
40
What is an example of an 8-aminoquinoline
Primaquine
41
Primaquine effects
``` MOA unknown - probably involves ROS Drug of choice for liver stages of vivax and oval (with CQ) gametocidal against all types well absorbed orally some resistance ```
42
Adverse effects of Primaquine
too toxic for long term Tx Contradicted in G6PD deficiency and pregnancy (predisposes to HEMOLYTIC ANEMIA) Avoid in patients with: granulocytopenia, methemoglobinemia, receiving myelosuppressive drugs (ex quinidine), or disorders that commonly include myelosuppression
43
What are 2 types of antifolates
Pyrimethamine and Proguanil
44
Fansidar [Pyrimethamine-Sulfadoxine]
Folate synthesis inhibitor slow acting erythrocytic schizonticides Sulfadoxine inhibits DHPS in malaria (can't make dihydrofolic acid) Pyrimethamine and Proguanil inhibit DHFR (can't make THF) overall decreases the formation of purines for DNA/RNA
45
Other uses of antifolates
Toxoplasmosis (Pyrimethamine + sulfadiazine (clindamycin can replace sulfadiazine)) Pneumocystis (SxT aka Bactrim; Atavaquone is alternative)
46
Use of Antifolates
Use of single antifolates is not recommended (resistance develops easily) Synergistic effect combination chosen b/c of matching pharmacokinetics (both have long half-lives) Resistance is spreading rapidly (no longer recommended)
47
Malarone
combination of proguanil and atavaquone Atavaquone MOA: disrupts mitochondrial electron transport Tx and prophylaxis usage Generally well tolerated (TAKE WITH FOOD) Atavaquone is alternative therapy for P. jiroveci
48
Antibiotics used as antimalarial drugs include
Tetracycline, doxycycline, and clindamycin are blood schizonticides They target components of the apicoplast Doxycycline commonly paired with quinine or quinidine for Tx for falciparum Doxycycline is used for chemoprophylaxis in mefloquine resistant areas
49
Drugs for Anaerobic Parasites
Metronidazole used for: E. histolytic, Giardiasis, trichomoniasis Kills trophozoites but not cysts usually followed by luminal drug to eliminate asymptomatic infection may target parasite DNA?? Tinidazole is a similar drug with less toxicity
50
Metronidazole and alcohol
Metronidazole inhibits acetaldehyde dehyrdrogenase --> acetaldehyde --> hypotension. nausea, vomitting, discomfort
51
What is Iodoquinol
``` luminal amebicide low bioavailabilty sole agent in "asymptomatic" carriers combine with metronidazole for amebic dysentery kills trophozoites ```
52
What is Pentamidine
parental administration mechanism unknown highly toxic First line agent for West African trypanosomiasis (alternative for visceral leishmania and pneumocystosis)
53
What is Nifurtimox
``` Most commonly used for T. cruzi MOA unknown (generate ROS??) reduces severity of acute phase (unlikely to completely eliminate parasite) orally available 3-4mo course of Tx Toxicity common ```
54
Miltefosine
``` phospholipid analog approved for use against visceral leishmaniasis 28 daily doses - almost 100% cure rate MOA unknown side effects tolerable TERATOGENIC - avoid during pregnancy ```
55
What is used to treat Giardia and Cryptosporidium
Nitazoxanide
56
What is used to treat T. cruzi
Nifurtimox or Benznidazole
57
What is used to treat T. brusei
West African - Early: Pentamidine; Late: Eflornithine East African - Early: Suramin; Late: Melarsoprol(not good)

Pharmacology (11 decks)

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