Anti-Malarials Flashcards

1
Q

what is the first-line anti-malarial?

A

chloroquine, but resistance is widespread

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2
Q

What is WHO’s first-line treatment for malaria if chlorquine resistant P. falciparum?

A

artemether-lumefantrine (Coartem)

target blood stages

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3
Q

which species of malaria cause a relapsing form (live in liver)

A

ovale - least common (Africa)

vivax - most common

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4
Q

P. vivax and falciparum make up what percentage of malaria infections?

A

95%

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5
Q

Where do the various agents act?

A
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6
Q

what is the only agent that acts at the hypnozoite stage?

A

primiquine

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7
Q

what are the only agents that acts at the hepatic schizont stages

A

primiquine

atovoquone-proguanil

(this occurs within 30 minutes of bite)

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8
Q

what agents only act at the blood schizont stage (not the gametocyte stage)

A

mefloquine

doxycycline

clindamycin

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9
Q

what agents act at the gametocyte stage (blood)

A

ACT

quinine

chloroquine

primaquine

atoquavone-proguanil

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10
Q

where do the artemesinins act?

A

blood stages of falciparum

some gametocyte of falciparum

asexual blood stages of vivax

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11
Q

what are the artemisinins?

A

artemether (PO/IM)

artesunate (rectal/IV)

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12
Q

what is the ADME of the artemesinins?

A

1-2 hr 1/2 life - not useful for prophylaxis

biliary excretion

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13
Q

what is the mechanim of action of the artemisinins?

A

peroxide bridge reduced by heme results in free radical production

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14
Q

What are the contraindications of the artemesinins?

A

1st trimester of pregnancy

children < 5kg

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15
Q

what are the S/E of the artemesinins?

A

decrease in RBC and neutrophils

transient heart block

*rare, dose, related; reversible

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16
Q

What is the ADME of Coartem?

A

Large Vd

t1/2= 4-5 days

absorption increased with high fat meal

drug-drug with antiretroviral/protease inhibitors

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17
Q

What are contraindications to ACT?

A

cardiac arrhythmias

cardiac disease

(kids and pregos)

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18
Q

what are the adverse effects of ACT?

A

Adults: GI distress, headache

Kids: fever, cough, vomiting, headache, anorexia

cardiac arrhythmias/neurologic symptoms with high doses

TAKE with fatty food or whole milk

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19
Q

what is the MOA of chloroquine?

A

inteferes with heme digestion

20
Q

what is the ADME of chloroquine?

A

CYP3A4 metabolism

renal excretion

loading does required - high doses usually fatal

21
Q

what’s the greatest thing about chloroquine?

A

It is safe in pregnancy!

22
Q

What are the AEs of chloroquine?

A

GI distress

headache

visual disturbances

urticaria

rare hemolysis (increased with G6PD deficiency)

23
Q

What are the contraindications of chlorquinolone?

A

epilepsy/myasthenia gravis

psoriasis/poryphia cutanea

advanced liver disease, blood disorders, severe GI or neurological disorders

can prolong QT

antacids delay absorption

decreases efficacy of yellow fever vaccine

24
Q

quinine acts on what stages?

A

falciparum asexual blood stages

gemetocyticidal against vivax and ovale

25
Q

What is the ADME of quinine?

A

oral, IM, IV (more toxicity)

readily absorbed, extensive tissue distribution

t1/2=11 hours

26
Q

what are the AEs of quinine?

A

Cinchonism: tinnitus, hearing loss, visual disturbance, headache, nausea, vomiting, dizziness, postural hypotension

rash, angiodema, bronchospasm

blackwater fever: severe hemolysis (STOP)

IV - hypoglycemia, hypotension

fatal arrythmia and ITP at 2-8 g

27
Q

what are the contraindications/cautions with quinine?

A

D/c if evidence of hemolysis

tinnitus/optic neuritis

caution: cardiac dysrhythmias

decrease dose in renal insufficiency

potentially safe in pregnancy (monitor glucose)

inhibits CYP3A4 (digoxin and warfarin)

28
Q

what are doxycycline, clindamycin and tetracycline good for?

A

adjunct therapy with quinine/quinidine

they act slowly in killing blood schizonts by inihibiting protein translation in protozoa

29
Q

when is primaquine active?

A

only agent that can eradicate liver stages of vivax and ovale

gametocytocial against falciparum

30
Q

what must you do before giving primiquine?

A

screen for G6PD deficiency

31
Q

What’s the MOA of primiquine?

A

interferes with mitochondrial ETC in parasite

32
Q

what is the ADME of primiquine?

A

large Vd

t1/2=3-8 h

rapid hepatic metabolism and renal excretion

33
Q

what are the contraindications of primiquine?

A
  • pregnant women
  • lupus and rheumatoid arth (if active)
  • hemolytic anemia in G6PD deficiency (x-linked)
    • 11% of AA males
    • Sardinians, Sephardic Jews, Greeks, Iranians
34
Q

what is the MOA of atovaquone?

A

inhibits mitochondrial ETC

35
Q

what is atovoquone active against?

A

asexual blood stages and primary liver stages in falciparum (ONLY)

36
Q

what is the ADME of atovoquone?

A

oral, lipophilic

slow absorption (increased with fatty meal)

t 1/2 2-3 days

no sig. metab, bilary excretion

37
Q

what is the mechanism of resistance to atovoquone?

A

cytochrome b mutations inhibit drug binding

38
Q

what are the AEs of atovoquone?

A

GI distress

headache

rash

risk can not be ruled out for pregos

rifampin/tetracycline reduce plasma levels

39
Q

what is proguanil active against?

A

asexual blood and primary liver stages of falciparum and vivax

40
Q

what is the MoA of proguanil?

A

inhbits dihydrofolate reductase

(enhances atovaquone effect)

41
Q

what is the ADME of proguanil?

A

slow absorption

t1/2=18-20 hours

hepatic metabolism (CYP2C19)

renal excretion

42
Q

is proguanil safe in pregnancy?

A

risk cannot be ruled out

43
Q

where does mefloquine act?

A

against asexual blood stages

44
Q

what is mefloquine used for?

A

prophylaxis and treatment of drug-resistant

falciparum

(best for prophylaxis)

MOA Unknown

45
Q

what is the ADME of mefloquine?

A

rapidly absorbed (variable)

extensive Vd

t/12-13-24 days (extensive protein binding(

CYP3A4 metabolism mainly biliary excretion

46
Q

what are the AE’s and contraindications of mefloquine?

A

GI distress and dizziness (short-term)

vivid dreams

black box: severe and permanent neuro and psych effects (10%)

2011: pregnant women, all trimesters CDC recommended

NO in seizures, depression bipolar

47
Q
A