2: Antiparasitics - Antimalarials Flashcards Preview

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1

which malaria is responsible for the most deaths?

plasmodium falciparum

2

which malaria is mostly in the tropics? what about the subtropics and temperate regions? west africa?

tropics: falciparum

subtropics/temp: vivax

west africa: ovale

3

which malarias can be relapsing? why?

vivax and ovale - hypnozoites in the liver

4

what are the 5 malaria parasites that cause disease in humans?

-falciparum
-vivax
-ovale
-malariae
-knowlesi

5

why is vivax generally less severe?

it is limited ti reticulocytes, whereas falciparum is not

6

what is important about the lifecycle of knowlesi?

24h life cycle - can increase in numbers very rapidly -> need treatment right away
-usually associated with zoonotic infections

7

describe the life cycle times for each malaria parasite?

liver stage ~7d

-falciparum, vivax, ovale: 48h cycles in blood
-malariae: 72h cycles in blood
-knowlesi: 24h cycles in blood

8

why is it a problem if a pregnant woman gets malaria?

malaria has receptors that bind chondroitin sulfate, which is prevalent in the placenta -> causes low birth weight and miscarriage

9

what are the classic symptoms of uncomplicated malaria?

-cold stage
-hot stage
-sweating stage

10

what are the more usual symptoms of uncomplicated malaria?

-fever and flu-like symptoms: chills, headache, myalgias, malaise
-anemia and jaundice

11

what are the symptoms of severe malaria?

-serious organ failures, including kidney
-cerebral malaria (abnormal behavior, impairment of consciousness, seizures, coma, etc.)
-severe anemia and hemoglobinuria due to hemolysis
-ARDS/ pulmonary edema
-placental malaria (especially during 1st pregnancy)

12

what are the types of drugs used for malaria?

-tissue schizonticides (kill liver stage)
-blood schizonticides (kill erythrocytic forms)
-gametocytocides (kill sexual stage, block transmission)

13

what is the only drug to kill malaria hypnozoites?

primaquine

14

what stage do all drugs work on?

asexual blood stages

15

when should you take malaria chemoprophylaxis?

before, during, and after travel

16

list 5 malaria chemoprophylaxis drugs

-atovaquone + proguanil (malarone)
-doxycycline
-chloroquine
-mefloquine
-primaquine

17

malarone:
1. what is it a combination of?
2. where is it useful?
3. when do you start/stop taking it?
4. how it is taken?

1. atovaquone + proguanil
2. all areas
3. start 1-2d prior, end 7d after
4. daily admin + short pretreatment

18

doxycycline:
1. where is it useful?
2. when do you start/stop taking it?

1. all areas
2. start 1-2d prior, end 4w after

19

chloroquine:
1. other names
2. where is it useful?
3. when do you start/stop taking it?

1. Aralen and generic
2. chloroquine sensitive areas (mostly C and parts of S Am)
3. start 1-2w prior, end 4w after

20

mefloquine:
1. other names
2. where is it useful?
3. when do you start/stop taking it?

1. Lariam and generic
2. mefloquine sensitive areas
3. start >2w prior, end 4w after

21

primaquine:
1. where is it useful?
2. when do you start/stop taking it?

1. if >90 vivax in area
2. start 1-2d prior, end 7d after

22

why do you start mefloquine so much earlier than the other malaria chemoprophylaxis drugs?

to determine if it gives you AE (it is associated with some toxicity), so then you can switch in time if need be

23

treatment for uncomplicated malaria or unidentified species in chloroquine sensitive areas?

chloroquine (aralen) and hydroxychloroquine sulfate (plaquenil)

add primaquine if find out ovale/vivax

24

treatment options for uncomplicated malaria or unidentified species in chloroquine resistant areas

-malarone (atovaquone + proguanil)
-coartem (artemether + lumefantrine)
-quinine sulfate + one of the following: doxy, tetra, clinda
-mefloquine (lariam)

add primaquine if find out ovale/vivax

25

treatment for complicated (severe) malaria: drug + what do you monitor?

-IV quinidine gluconate + doxy, tetra, or clinda
-consult cardiologist or experiences physician
-monitor BP (hypotension), cardiac fxn (widening of QRS or long QT), serum glucose (hypoglycemia)
-severe cardiac complications may warrant temporarily discontinuing treatment or decreasing infusion rate

26

what is an alternate treatment for complicated malaria if quinidine gluconate is not tolerated or not available?

artesunate - IV only
-followed by one of the following: malarone, doxy (clinda in preggers), or mefloquine

27

what is the first line treatment in most of the world except for the U.S.?

artemisinin

28

what type of chemical is artemisinin?

blood schizonticide
-sesquiterpene lactone endoperoxide (endoperoxide is active group)

29

artemisinin: mechanism of action

must be activated likely via heme-irione, and activated form may form free radicals that target parasite proteins/lipids
-potent and fast-acting (10,000-fold reduction in 48h)
-low toxicity

no effect on liver stages

30

artemisinin: mechanism of resistance

-mutations in Kelch 13 gene
-delays progress through life cycle
-may alter stress response