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PPP 249 SPRING QUARTER 2023 > Antiparasitic Drugs > Flashcards

Antiparasitic Drugs Flashcards

1
Q

What are the 2 distinct forms of a parasite?

A
  1. Single celled protozoa
  2. Multicellular Metazoa (helminths)
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2
Q
  1. Extraintestinal protozoal infections due to?
  2. Intestinal protozoal infections due to?
A
  1. Plasmodium species
  2. Entamoeba histolytica and Giardia Lamblia
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3
Q

Name some examples of Metazoa (2) and then name their subtypes

A
  1. Flat worm –> Trematodes and cestodes
  2. Roundworm (nematodes) -> ascariasis, hookworm, pinworm
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4
Q

What’s the clinical presentation for malaria (an extra intestinal protozoal infection)?
-Abrupt onset of?
-Followed by?

A

Coldness and chills,
high fever, HA, N/V

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5
Q

Name organism that causes malaria
-name the 4 types of that organism
-State which one is involved in the most severe disease
-State which one if involved in most COMMON Disease

What’s the vector for malaria?

A
  1. Plasmodium

-Plasmodium falciparum, vivax, malariae, and ovale

  • Plasmodium falciparum

-Plasmodium falciparum + vivax

Female mosquito (Anopheles)

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6
Q

ANTI-MALARIALS : Quinoline Derivatives

  1. Name 2
  2. State their MOA
  3. What stage of malaria is affected by these quinolone derivatives?
A
  1. Quinine and quinidine
  2. They block the stacking of Heme into hemozoin so that heme can continue to be toxic to malaria
  3. Everything in red blood cell. Trophozoite replication into schizont, merozoite, and gametocytes
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7
Q

Pharmacokinetics :
1. What’s the admin forms of quinine and quinidine? Also include quinine half life and dosing regimen

  1. Clinical uses for each?
A
  1. Quinine = PO. Short half life, administration TID

Quinidine = IV or PO. But the IV form discontinued

  1. Quinine po = TX of drug resistant P.falciparum infection (bc of its toxicity and short half life its not used for chemoprophylaxis)

Quinidine IV : severe malarial infection (discontinued in 2019)

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8
Q

Quinoline Derivs Quinine + Quinidine
1. AE’s ? G,C,C,H
(Which ae happens with Quinine only)

A
  1. GI effects

Cardiac Effects -> QT prolongation -> TdP blockade of K channels

Cinchonism -> Ears : tinnitus, eyes : disturbed vision , CNS -> Headaches, Dizziness

Hematologic Effects (quinine only). Acute Hemolytic anemia in pt with G6PD deficiency

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9
Q

CI/Precautions for Quinoline Derivs Quinine + Quinidine ? (1)

Interactions ? (2)

A
  1. G6PD deficiency (quinine only)
  2. Inhibits CYP2D6
    Inhibits P-glycoprotein transporter
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10
Q

Quinoline Derivs : Chloroquine + Hydroxychloroquine

  1. MOA?
  2. Clinical uses?
    (Tx and prophylaxis of? Used in Combo with what for what?)
A
  1. Similar to quinine : inhibits hem-polymerase activity leading to toxic build up of heme
  2. TX and prophylaxis of non resistant P. Falciparum and P. Malariae
    - Used in combo with PRIMAQUINE for eradication of hepatic stages of P.vivax + P.ovale
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11
Q

Quinoline Derivs : Chloroquine + Hydroxychloroquine

  1. AE’s? (4)
  2. Safe in ?
  3. CI/precautions in ?
A
    • GI –> N/V/D
    • Cardiac such as QT prolongation
      -Pruritus
      -Visual Disturbances
  2. Pregnancy
  3. Psoriasis + Ocular Disease
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12
Q

Quinoline Derivs : Mefloquine (Lariam)

  1. MOA?
  2. Clinical uses? (talk about dosing and tx)
  3. AE’s? (3 categories G,C,C)
A
  1. same as quinine : inhibits hem-polymerase activity leading to a toxic build up of heme
  2. Prophylaxis (once weekly dosing!) and tx of drug resistant P.falciparum
  3. GI -> N/V/D
    Cardiac Effects -> QT prolongation
    CNS sx’s bc crosses BBB –>
    Vivid dreams (common), HA, anxiety, Psychosis, seizures
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13
Q

Quinoline Derivs : Mefloquine

  1. CI? (5) These are all BBW
    E,P,S,D,A

Quinoline Derivs : Primaquine
1. MOA?
2. Active against?
3. Highly ___ against all 4 malaria species
4. WHat stage of malaria is it going to affect?

A
  1. Epilepsy, psychosis, schizophrenia, depression, anxiety
  2. Unknown, prob via generating ROS
  3. Hepatic Stages of P.vivax + P.ovale
  4. Gametocidal
  5. It will kill off the hypnozoite so that it cant regenerate and form a schizont
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14
Q

Primaquine Clinical Use?
- Used in Combination with ___ for ____
-Only agent active against?

Primaquine AE’s ? (G,C,H)

For the hematologic effects, u must counsel ur pt’s to do what?

A
  1. Chloroquine, eradication of P.vivax and P.ovale
  2. Dormant hypnozoite stages of P.vivax and P.ovale
  3. GI, Cardiac –> QT prolongation, Hematologic effects –> Hemolysis and hemolytic anemia;high risk in pt’s with G6PD deficiency (must test for G6PD)
  4. Look for dark or blood colored urine which indicates hemolysis
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15
Q

Primaquine : CI? (2)
It induces what? So caution with which drug?

A

Pt’s with G6PD deficiency + Pregnancy

CYP1A2 –> Caution with drugs metabolized via CYP1A2 (Warfarin)

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16
Q

Antimalarials : Artemisinin +Derivs

  1. Name 3
  2. Isolated from ?
  3. Very ___ and ____
  4. More rapid ___ and ___ than any other currently licensed antimalarial drug
  5. Diff formulations such as?
  6. MOA?
  7. What stage of malaria cycle does it affect?
A
  1. Artesunate, Artemether, Dihydroartemisinin
  2. Artemisia annua (qinghoa, sweetworm wood)
  3. potent, fast acting
  4. parasite clearance, fever resolution
  5. Oral, IM, IV, IR
  6. bind iron, break down peroxide bridges-> production of free radicals -> Damage parasite
  7. Red blood cell stage . Trophozoite to schizont and gametocytes
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17
Q

Artemisinin + Derivs

  1. PK –> It is rapidly __ , peak plasma levels ___
    - half life is __
  2. Used for tx of?
    - FDA approved as ? (type of tx and name)
  3. Also for tx of ? State the drugs + admin route?
A
  1. absorbed, 1-2 hrs
    1-3 hrs
  2. UNcomplicated Falciparum Malaria
    - Artemisimin based combo therapy -> Artemether - lumefantrine
  3. Complicated Falciparum Malaria
    -artesunate (IV or IR), artemether (IR)
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18
Q

Artemisinin + Derivs : AE’s + CI

GI ? CNS? CI in?

A

GI -> N/V/D
CNS : Dizziness
CI -> First trimester of pregnancy and Children < 5kg

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19
Q

Antimalarials : Antifolates
-Chemoprophylaxis with ____ no longer recommended . Use __?
-Formulations?

A

single folate antag . combination regimen

Atovaquone and Proguanil

20
Q

Antifolates : Atovaquone and Proguanil

  1. MOA of each ingredient?
  2. Which part of malarial stage does this effect?
A
  1. Atovaquone : Disrupts mitochondrial electron transport in parasite which disrupts nucleotide synthesis

Proguanil : DHFR inhibitor

  1. The Schizont in RBC + Schizont in hepatocytes
21
Q

Antifolates :Atovaquone and Proguanil

  1. Treatment and prophylaxis of?
  2. AE’s ? (2)
  3. CI?
A
  1. Chloroquine-resistant P. falciparum
  2. GI effects -> ABD Pain , N/V/D
    Other : Mild + reversible elevation of liver enzymes
  3. Pregnancy
22
Q

Antimalarials : Misc Antibiotics

  1. Name 3 antibiotics used
  2. MOA : Inhibition of? Slow acting?
  3. Clinical uses (2) ?
    alone for ___
    Ineffective as ?
  4. What stage of malaria does this effect?
A
  1. Tetracycline, doxycycline, clindamycin
  2. inhibition of protein synthesis in parasite apicoplast , slow acting blood schizonticides
  3. Alone for chemoprophylaxis
    Ineffective as single agents for malaria tx -> Use in conjunction with quinine + quinidine
  4. Schizont in erythrocytes or rbc
23
Q

Antimalarial therapy Decisions

After history of travel to malaria-endemic area or clinical suspicion of malaria -> perform a ?
If positive, evaluate _____, and determine ___

A

-thick and thin blood films
-clinical status and disease severity
-Parasite density

24
Q

For UNcomplicated malaria, that is NON-Falciparum Malaria but is P. malariae, use which drugs? (2)

If it is P.Ovale or P. vivax use which ? (3)

A

chloroquine or hydroxychloroquine

chloroquine or hydroxychloroquine PLUS primaquine (if not G6PD deficient)

25
Q

For UNcomplicated malaria, that is indeed Falciparum Malaria , state which drugs u should use in the following cases :

  1. Acquired in chloroquine-sensitive areas (1)
  2. Acquired in chloroquine-resistant areas (4)
  3. Acquired in mefloquine resistant areas (3)
  4. For COMPLICATED MALARIA What drug should you use?
A
  1. Chloroquine or Hydroxychloroquine
  2. Atov-proguanil OR Artemether-Lumefantrine OR quinine plus tetracycline or doxycycl or clindamyc OR Mefloquine
  3. Atov-proguanil OR Artemether-lumefantrine OR quinine plus tetra or doxy or clinda
  4. Artesunate (IV) . Switch to oral meds to complete the tx regimen after appropriate clinical response
26
Q

Antimalarial Chemoprophylaxis : State the drug u would use in the following

  1. Areas with chloroquine-sensitive malaria (2)
  2. Areas with chloroquine resistant malaria (3)
  3. Areas with principally P.vivax (1)
  4. Antirelapse therapy (terminal prophylaxis)
A
  1. chloroquine or hydroxychloroquine
  2. Atovaquone-proguanil or DOXYcycline or Mefloquine
  3. Primaquine (if not G6PD deficient)
  4. Primaquine (if not G6PD deficient)
27
Q

Intestinal Protozoal Infections : Amebiasis

Species : Entamoeba histolytica
Two forms ?

A

Cyst (Ingested form)

Trophozoite (motile feeding form, causes pathology, invasive disease)

28
Q

Intestinal Protozoal Infection Process
1. Ingestion of?
2. Cysts are resistant to? and pass through ?
3. In ___ the cysts excyst to form ?
4. These multiply, colonize the ____ and also form ? Cysts and Trophozoites exist in?
5. Trophozoites can also invade and colonize ___. If trophozoites move into __ they can infect sites such as __, ____, and ____

A
  1. Contaminated food or water
  2. Gastric content, small intestine
  3. Small intestine, trophozoites
  4. mucus layer of the colon, new cysts , stool
  5. Epithelium (amebiasis) . bloodstream, liver, lung, brain (extraintestinal disease)
29
Q

Amebiasis
Disease State : In most people is ___
Can cause ___
Extraintestinal manifestation would be ___

A

-Asymptomatic
-Amebic Dysentry = inflamm diarrhea = blood and pus in stool
-Liver Abscess

30
Q

Amebiasis Treatment
Goal is to eliminate invading trophozoites and eradicate intestinal carriage of the organism –> Use of ____ to eradicate ___ and a luminal amebicide to ____

If asymptomatic use? (2)
If experiencing intestinal disease use ? (3)
If extraintestinal disease use? (3)

A

Metronidazole (or Tinidazole) , tissue trophozoites, eradicate intestinal cysts

iodoquinol or paromomycin

metronidazole followed by paromomycin or iodoquinol

metronidazole followed by paromomycin or iodoquinol

31
Q

Therapy for Amebiasis : Metronidazole
MOA : its a ___. requires?
-Generates ___ –> disrupts DNA –> cell death

Clinical use? Tx of (3)

A

pro drug, reduction of Nitro-group

free radicals

amebiasis (wit or w/o extraintestinal manifestation), giardiasis, trichomoniasis

32
Q

Therapy for Amebiasis : Tinidazole
-MOA, PK and AE v similar to metronidazole
-Clinical uses? (3)

Therapy for Amebiasis : Paromomycin (AG antibiotic)
-MOA : binding to ___ -> interfere with ___ -> inhibition of ___
-PK : poor ___, ___ only, NOT ALONE for tx of ___

A
  1. Amebiasis , Giardiasis, Trichomoniasis

30s subunit, initiation complex, protein synthesis

absorption, oral use, extraintestinal disease

33
Q

Paromomycin : Clinical Uses ? (2)

  1. AE’s? (2)
A
  1. Amebiasis (for asymptomatic pt’s and together with metronidazole for pt’s with intestinal disease)
  2. Giardiasis
  3. GI like N/V/D
    Rash (rare)
34
Q

Therapy for Amebiasis : Iodoquinol
MOA : unknown but effective against organisms in ___
Clinical use?
AE’s (2) ?

A

bowel lumen

amebiasis

GI effects -> mild diarrhea (TAKE WITH MEAL)
Enlargement of thyroid

35
Q

Giardiasis
Species is Giardia Lamblia
Two forms are ?

A

Cysts : ingested form , viable outside the body for long periods

Trophozoites : Pathology causing , flagellated, destroyed by gastric acidity

36
Q

Giardiasis Intestinal Spread
1. Ingestion of contam water or food
2. Cysts resistant to ___ and pass thru small intestine
3. Here, they excyst to release ____
4. Trophozoites multiply in small intestine and attach to ____ causing ___,___ and ___
5. Trophozoites can move to the __ and produce ___ that can be passed in feces
6. Cysts and trophozoites found in stool

A
  1. gastric content
  2. 2 trophozoites
  3. villous surface of SI, abdominal pain, cramping, dystentery
  4. colon, cysts
37
Q

Giardiasis
Disease : Presentation of diarrhea?
Who can develop more severe disease?

TX : What do you use for systemic action and which agent is used for luminal action?

A

Fatty, foul smelling(May range from asymptomatic to fulminant diarrhea and malabsorption)

PT’s with weakened immune system (HIV, cancer, transplant, elderly)

Metronidazole + tinidazole + nitazoxanide

Paromomycin (lower efficacy but safer for pregnancy)

38
Q

Giardiasis Therapy : NITAZOXANIDE
MOA : Unknown but may interfere with?
PK : Well ____
Clinical uses (3) ?

AE’s –> GI ?? (2)

A

electron transfer reaction
absorbed

giardiasis, cryptosporidiosis , infectious diarrhea

Abdominal pain (take with meal) and diarrhea

39
Q

For disease caused by Metazoa, specifically roundworm , which drugs provides coverage for roundworm subtypes ascariasis, pinworm, AND hookworm?
Which drug covers Ascariasis, pinworm, but not hook worm?

A

Albendazole + Pyrantel Pamoate

Ivermectin

40
Q

antiHELMINTHICS : Benzimidazoles such as ALBENDAZOLE
MOA : Intereferes with ___ –> inhibits ___ and ___
PK : Has poor absorption, how to incr abs?
What’s route of metabolism?

Clinical uses (2)?

AE? -> GI effect is mild, but long term tx leads to?

CI in?

A

microtubule synthesis , cell replication , microtubule-dependent glucose uptake

administer with high fat meals (peanuts, ice cream)
hepatic ; rapid sulfoxidation to active metab

particularly effective in treating GI nematodes (poor abs doesnt limit use)
-Cysticercosis

elevation of liver enzymes

pregnancy + hepatic disease

41
Q

Pyrantel Pamoate
MOA : ?
PK : Poor abs -> used for tx of ?
Clinical use?

AE’s? (3)

A

neuromusc blocking agent ; causes incr in ACh release and inhibition of AChE -> paralysis of worm

luminal organisms

Intestinal helminths : roundworms, pinworm, hook worm

GI effects, Dizziness, Elevation of liver enzymes

42
Q

Ivermectin
MOA: ___ agonist
-Binds with ___ (found only in invertebrate nerve and muscle cells) –> Incr ___ of cell membranes to ____ ions -> Hyperpolarization of nerve or muscle cell -> ___

PK : Does not pass ___. wide ___

Clinical use : Severe intestinal ____ (NOT ___)
Kills ____, not ____. wait until adult worm dies
-DOC for ? (2)

A

GABA
glutamate gated Cl- channels , permeability CL, death of parasite

BBB , tissue distribution

nematodes, hookworm. Larval stage, adult worms.

Strongyloidiasis , onchocerciasis

43
Q

Ivermectin
AE’s (2)
CI?

A

Diarrhea and pruritus

Pregnancy

44
Q

If patient has Metazoa disease from flat worms, specifically tapeworms with an invasive cestode infection, what drug do u use?

If tapeworms or flukes, noninvasive + invasive cestode infections and schistosoma, what drug do u use?

A

Albendazole

Praziquantel

45
Q

Praziquantel
MOA : Increases ___ to ___ causing marked ___ initially and then ___. Promotes influx of Ca and possibly interacts with variant Ca-channel which is found in __ and other __

Clinical use for ?

AE’s (3) ?

A

membrane permeability, Ca, contraction, paralysis
schistosomes, praziquantel sensitive parasites

Schistosomiasis (DOC)
Cysticercosis and many intestinal tapeworms

N/V/D, HA/Dizzy, Pruritus

PPP 249 SPRING QUARTER 2023 (11 decks)

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