Anti-Protozooals Flashcards

1
Q

How do we get malaria?

A
  • sporozoites are transmitted through mosquito (vector) saliva into host. They go to the liver and then go on to infect the RBCs.
  • remember vectors bite twice (once to get infected, and once to transmit).
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2
Q

What is chloroquine (CQ)?

A
  • 4-aminoquinolone that interferes with the malaria parasite’s (plasmodium) heme detoxification. It kills only the erythrocytic stage of infection.
  • asexual malaria parasites flourish in host erythrocytes by digesting Hb in their acidic fluid vacuoles, a process that generates free radicals and heme (toxic to the parasite). However, they sequester heme as an insoluble unreactive malarial pigment called HEMOZOIN.
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3
Q

What is quinine?

A
  • similar to chloroquine (inhibits parasite’s heme detoxification).
  • alkaloid derivative from Peruvian bark of Cinchona tree.
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4
Q

What can quinine toxicity cause?

A
  • cinchonism= tinnitus, headache, and dizziness
  • hypoglycemia
  • blackwater fever (can come from malaria also)= hemoglobinuria
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5
Q

What is mefloquine?

A
  • 4-methanolquinoline= highly effective blood schizonticide used for malaria.
  • contraindicated in pts on B-blockers.
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6
Q

What is a toxicity of mefloquine toxicity?

A
  • neuropsyychiatric (dysphoria, somnolence, vivid dreams, encephalopathy, psychosis, depression, seizure).
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7
Q

What is atovaquone?

A
  • hydroxynaphthoquinone= inhibitis pre-erythrocytic development of parasite in liver and interferes with cytochrome electron transport and DNA replication.
  • used for malarai (plasmodium), pneumocystis jiroveci, T. gondii, and Bebesia
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8
Q

What is Proguanil?

A

biguanide that is metabolized via P450. Inhibits plasmodial dihydrofolate reductase.

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9
Q

** What is malarone?

A
  • combination of Atovaquone + Proguanil.

* not recommended in children, pregnancy or breast feeding women.

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10
Q

What other drug can treat plasmodium (malaria)?

A

tetracycline (doxycycline)

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11
Q

** What is primaquine?

A
  • 8-aminoquionoline= effective against intrahepatic forms of plasmodium (malaria) and RELAPSING malaria (hypnozoite formation). It damages plasmodial mitochondria via oxidative stress.
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12
Q

What is a problem with primaquine?

A
  • causes hemolytic anemia in patients with G6PD deficiency.

- never give parenterally= marked hypotension.

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13
Q

What are artemisinins?

A
  • “sweet wormwood,” potent and rapidly acting blood schizonticide that inhibits calcium adenosine triophosphatase, destroying plasmodium via free radical release (attacks parasite cell membrane).
  • used in other countries.
  • induces P450
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14
Q

What is sulfadoxine-pyrimethamine?

A
  • limited use for malaria because of serious ADRs
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15
Q

What is pyrimethamine?

A
  • blocks synthesis of nucleic acid and folate in plasmodium and T. gondii.
  • company raised price of this drug a few years ago causing issues.
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16
Q

Can quinine induce abortion?

A

YES :(

17
Q

Besides plasmodium species, what are the other 2 intra-erythrocytic organisms?

A

Bebsia (pig borne) and Bartonella

18
Q

What 2 drugs can we use to treat COMPLICATED malaria?

A
  1. Guinidine gluconate (IV) then switch to oral.

2. Artesunate

19
Q

Is there some immunity in malaria?

A

may be some but not a lot

20
Q

What is Dapsone?

A
  • widely used Rx of leprosy, PCP, toxoplasmosis, and leishmaniasis.
  • inhibits plasmodial dihydropteroate synthase, folic acid synthesis.
21
Q

What is dapsone syndrome?

A
  • rash, fever, jaundice, and eosinophilia
22
Q

What is metronidazole?

A
  • antibiotic used for anaerobic bacteria and protozoa. It forms free radical metabolites that causes DNA damage and death of organism.
23
Q

What can metronidazole toxicity cause?

A
  • disulfiram-like effect= abdominal distress, vomiting, flushing, and headache with alcohol consumption.
  • peripheral neuropathy
  • enceophalopathy
24
Q

What is pentamidine?

A

inhibits DNA, RNA, protein, and phospholipid synthesis used for trypanosomiasis, pneumocystis jiroveci, and leishmaniasis

25
Q

For what is miltefosine used?

A
  • leishmaniasis
26
Q

*** For what is nitazoxanide used?

A
  • cryptosporidiosis and giardiasis
27
Q

For what is furazolidone used?

A
  • giardiasis
28
Q

What parasite is paromycin (aminoglycoside) sometimes used?

A
  • Entamoeba histolytica