Antiprotozoal Agents Flashcards

1
Q

These parasitic infectious organisms can all be treated with what?

  • Amebiasis (Entamoeba histolytica
  • Trichomoniasis (T. vaginalis)
  • Giardiasis (Giardia lamblia)
A

Metronidazole

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2
Q

What is the name for worm diseases?

A

Helminthic

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3
Q

These worms can all be treated with what agent?

  • Hookworm (Necator americanus)
  • Roundworm (Ascariasis)
  • Pinworm (Enterobiasis)
A

Albendazole

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4
Q

Hookworm (Necator americanus) is found where in the US?

A

Southeastern US

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5
Q

Roundworm (Ascariasis) is found where in the US?

A

Appalachia

Gulf Coast

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6
Q

Pinworm has the most cases out of the three worms French presented to us at how many million? Cases mostly seen in which population?

A

42 million
Children
** Can be treated with albendazole but ALSO Pyrantel

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7
Q

Malaria can infect which two areas of the body? Which has higher mortality?

A

Blood (erythrocytic) = P. falciparum
Liver (exoerythrocytic) = P. vivax, P. ovale

*Blood has highest mortality, responsible for 85% of deaths

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8
Q

What is important to consider when treating malaria?

A

Resistance patterns of geographic regions

*P. falciparum (blood) chloroquine resistance becoming more prevalent

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9
Q

What is the vector for malaria?

A

Plasmodium-infected mosquitos

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10
Q

You have a pt traveling to Mexico-Caribbean and wants PROPHYLAXIS tx for malaria. What should you know about this area and what is the tx?

A

Mexico/Caribbean is chloroquine SENSITIVE

Tx: chloroquine 1-2 wks prior to travel and 4 wks after

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11
Q

You have a pt traveling to South America (South Africa and Asia to be specific) and wants PROPHYLAXIS tx for malaria. What should you know about this area and what is the tx?

A

South Americas (South Africa and Asia) are chloroquine RESISTANT

Tx: Atovaquone/proguanil daily 1-2 days prior travel and 1 wk after

Doxycycline: daily 1-2 days prior and 4 wks after

Mefloquine: Weekly 1-2 wks prior and 4 wks after

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12
Q

Tx for non-falciparum (i.e. P. ovale and P. vivax)

A

Tx (acute): Chloroquine

Tx (resistant): Mefloquine or atovaquone-proguanil or quinine + doxycycline

*Liver form (aka hypnozoite) to prevent relapse = Primaquine

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13
Q

Tx for P. falciparum?

A

Artemisinin combinations PLUS mefloquine OR sulfadoxine-pyrimethamine

OR

atovaquone-proguanil OR quinine + doxycycline or clindamycin

*Don’t forget P. falciparum has widespread chloroquine resistance

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14
Q

Tx for SEVERE P. falciparum?

A

artemisinin IV OR quinine/quinidine IV + antimicrobial

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15
Q

What is the mechanism of action (MOA) of chloroquine?

A

Interferes with feeding mechanism of parasite by raising blood pH (alkaline).

*Selective toxicity depends on drug concentration in parasite (25X plasma level)

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16
Q

How is chloroquine absorbed and what would you tell your pts to avoid while dosing?

A

Rapid and complete oral absorption

Tell pts to avoid antacids as it hinders absorption

17
Q

Where does chloroquine concentrate in the body?

A

Liver and kidneys, has large Vd (volume distribution) therefore needs LOADING DOSE

18
Q

What method of administration do you NOT give chloroquine?

A

IM = hypotension, shock, sudden death

  • high total doses over 100 grams = ototoxicity, myopathy and IRREVERSIBLE retinopathy
  • Children especially sensitive to toxicities
19
Q

Mefloquine is related to quinine and is less toxic, but was given a black box warning in 2013 which contraindicates use for who?

A

Pts w/ neurologic and psychiatric disorders

Also pts with heart conduction abnormalities

20
Q

Of the quinolines which is the most toxic?

A

Quinine = narrow therapeutic window

  • given parenterally for acute infection
  • overdose = cardiotoxicity, blindness and deafness
21
Q

Of the quinolines which is the least toxic?

A

Primaquine. It is also the most effective antimalarial

Good for radical cure (liver stages)

22
Q

Who would you avoid giving primaquine to? Think of blood disorders.

A

G6PD deficiency = hemolysis

contraindicated in pregnancy

23
Q

What is the MOA of primaquine?

A

Drug metabolites act as oxidants via unknown mechanism

24
Q

What is the drug of choice for severe falciparum malarial infection?

A

artesunate IV (most rapid and potent onset)

Artemether PO after above therapy

25
Q

What are some ADRs of artesunate? What do you monitor pts for after tx?

A

2-9% = acute renal failure, sepsis, coma, seizure, shock, respiratory failure

Monitor for 4 wks for possible severe post-tx hemolytic anemia