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[Ther 201] Exam 3 Flo Cluster > Lec 03: Antiparasitics > Flashcards

Lec 03: Antiparasitics Flashcards

1
Q

Which of the following antiprotozoal drugs is the chemotherapy for amoebiasis:

a. paromomycin
b. metronidazole
c. diloxanide furoate
d. AOTA

A

d. AOTA

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2
Q

Drugs for malaria:

A 
Chloroquine
Primaquine
Sulfadoxine + Pyrimethamine
Quinine
Tetracycline artemether - lumefantrin
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3
Q

Drug for giardiasis

A

Metronidazole

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4
Q

Amoebiasis is caused by:

a. Entamoeba coli
b. Entamoeba dispar
c. Entamoeba histolytica
d. AOTA

A

c. Entamoeba histolytica

All the others are non-pathogenic entamoeba although E. dispar and E. histolytica are morphologically similar

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5
Q

When can one distinguish between E. dispar and E. histolytica?

A

When there is ingested RBC since E. histolytica can destroy the intestine

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6
Q

How do protozoans move and acquire food?

A

Pseudopodia

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7
Q

MIXED OR LUMINAL AMEBICIDE: eradicates both intestinal and systemic amoeba

A

MIXED (ex. Metronidazole)

‘Mixed’ or ‘Luminal’ refers to the localization of effect ng amebicide. Obviously ang effect ng luminal amebicides ay sa loob lang ng intestinal lumen.

Examples ng luminal amebicide: Diloxonide, paromomycin

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8
Q

Mechanism of Action of Metronidazole?

A

N group of the drug accepts electron from the ferrodoxin (protein found in many anaerobic bacteria) of amoeba -> Reductive Bioactivation -> Production of cytotoxic products in ameoba -> damage to dna and internal proteins -> death of amoeba

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9
Q

Which of the following is NOT an indication for the use of Metronidazole?

a. brain abscess caused by Bacteroides fragitis
b. trichomoniasis
c. tetanus treatment
d. NOTA

A

d. NOTA

Other indications include:

  • giardiasis
  • bacterial vaginosis
  • ulcer (H. pylori)
  • antibiotic-induced pseudomembranous colitis (C. difficile)
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10
Q

TRUE or FALSE: Metronidazole has good oral bioavailabilitiy.

A

TRUE.

Oral bioavailability is 90-100%.

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11
Q

TRUE or FALSE: Metronidazole is mainly excreted in feces.

A

FALSE.

Urine

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12
Q

TRUE or FALSE: When metronidazole is metabolized to hydroxymetronidazole, it no longer has any antibacterial activity

A

FALSE.

Hydroxymetronidazole is 60-80% bioactive

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13
Q

TRUE or FALSE: Metronidazole has a longer half-life than Hydroxymetronidazole

A

FALSE.

T1/2 of both is 6-12 hours.

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14
Q

TRUE or FALSE. Metronidazole can be distributed into the CSF

A

TRUE.

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15
Q

TRUE or FALSE: Metronidazole can cause pancreatitis.

A

TRUE.

Other ADRs include:

  • Some patients said that taking the drug feels
    worse than amoebiasis
  • Nausea, headache, vomiting, abdominal cramps
  • Dry mouth with metallic taste
  • Pancreatitis
  • Ataxia, encephalopathy, seizures, dizziness,
    vertigo
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16
Q

When this drug is given with alcohol, a disulfiram-like reaction occurs.

A

Metronidazole

  • Disulfiram is a drug used to treat chronic alcoholism by inhibiting alcohol dehydrogenase, thus producing acute sensitivity to alcohol leading to flushing, sweating, throbbing headache, nausea, confusion w/in minutes, vomiting & hypotension
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17
Q

This drug affects amoeba before encystment (although MOA is still unknown)

A

Diloxanide Furoate

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18
Q

Metronidazole, Paromomycin or Diloxanide Furoate: Which amebicide causes flatulence?

A

Diloxanide Furoate.

Other ADRs:

  • dry mouth urticaria
  • pruritus
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19
Q

Which of the ff. species of Plasmodium is the most common cause of malaria in the Philippines?

a. P. falciparum
b. P. vivax
c. P. ovale
d. P. malariae

A

a. P. falciparum.

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20
Q

P. falciparum in the Philippines is NOT currently resistant to which of the following antimalarials:

a. Artemether
b. Chloroquine
c. Fansidar
d. Coartem

A

d. Coartem (Artemether-lumefantrine)

It is currently the first-line treatment for malaria.

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21
Q

What are the life stages of Plasmodium?

A
  1. Exo-erythrocytic cycle (in liver of human)
  2. Erythrocytic cycle (RBC of human)
  3. Sporogonic cycle (gut of mosquito)
22
Q

Which area in the Philippines has the most reported cases of malaria?

a. Ilocos
b. Palawan
c. Visayas
d. Davao

A

b. Palawan

23
Q

BLOOD or TISSUE Schizonticide: Which has no effect on hepatic stages of Plasmodium?

A

BLOOD Schizonticide

ex: chloroquine, mefloquine, fansidar, quinine, artemisinin derivative

24
Q

BLOOD or TISSUE Schizonticide: Primaquine

A

Primaquine lang ang TISSUE Schizonticide sa trans hahaha.

*Schizonticide: an agent selectively destructive of the schizont of a sporozoan parasite (Plasmodium)

25
Q

Treatment regimen for Day 2 of uncomplicated vivax malaria consists of:

A

Chloroquine 150 mg base tablet; 5 mg/kg so approx. 4 tablets/day (adult)

Day 0-1: Chloroquine 150 mg base tablet; 5mg/kg - 2 tablets/day (adult)

Day 2: Chloroquine 150 mg base tablet; 5 mg/kg so approx. 4 tablets/day (adult)

Day 3-17: Primaquine 15 mg base tablet; 0.5 mg/kg/day so for adults, about one tablet each day.

26
Q

What dose of primaquine is given as part of treatment regimen for uncomplicated vivax malaria for patients with mild to moderate G6PD deficiency?

A

Instead of 0.5mg/kg of body weight/day from Day 3 to 17 of treatment, it is instead given at 0.75 mg/kg of body weight ONCE A WEEK for 8 WEEKS.

*Primaquine is contraindicated in SEVERE G6PD Deficiency

27
Q

Prophylaxis given for malaria is:

a. Chloroquine
b. Mefloquine
c. Doxycycline
d. b & c only
e. AOTA

A

d. b&c only
* MEFLOQUINE is taken ONCE WEEKLY in a dosage of 250 mg starting 1-2 WEEKS BEFORE ARRIVAL and continuing THROUGH the trip and for 4 WEEKS AFTER DEPARTURE. On the other hand, DOXYCYCLINE is given DAILY.

28
Q

What is the current Second-line treatment for uncomplicated falciparum malaria?

A

Quinine (QN) oral

29
Q

TRUE or FALSE: Oral absorption of Artemether-Lumefantrine (coartem) is improved when taken with food.

A

TRUE.

According to Novartis Pharma: “ Food enhances the oral absorption of artemether and lumefantrine. In healthy volunteers, the relative bioavailability of artemether increased by two- to threefold and that of lumefantrine by sixteenfold when administered after a high-fat meal as opposed to under fasted conditions.”

30
Q

Increased plasma concentrations of coartem can be caused by substances that affect:

a. CYP2D6
b. CYP2C19
c. CYP3A4
d. AOTA

A

c. CYP3A4

As an example, GRAPEFRUIT JUICE inhibits CYP3A4-mediated first-pass METABOLISM leading to increased plasma concentrations of artemether-lumefantrine.

31
Q

Cinchonism is the toxic effect of which antimalarial?

a. Mefloquine
b. Coartem
c. Quinine
d. Chloroquine

A

c. Quinine

Derived from the bark of CINCHONA tree in 1820
and has been a traditional South American
remedy for intermittent fevers

  • Cinchonism: GIT distress,
    headeache, vertigo, blurred vision, tinnitus
32
Q

MOA of Quinine?

A

It complexes with dsDNA preventing separation and ultimately, DNA replication.

33
Q

Which drug causes hemolysis w/ G6PD deficiency?

a. Fansidar
b. Coartem
c. Tetracycline
d. Quinine

A

d. Quinine

Other drugs which may cause hemolysis in G6PD-deficient patients: CHLOROQUINE(very rare), PRIMAQUINE

  • Other ADRs of Quinine include:
- hypersensitivity: skin rashes, 
urticarial, angioedema, bronchospasm; 
- leucopenia, 
- granulocytosis,
- thrombocytopenia
- hypoglycemia in severe infections in pregnant patients
34
Q

This antimalarial drug is not usually used unless you’re sure that it is vivax malaria.

a. Chloroquine
b. Coartem
c. Tetracycline
d. Quinine

A

a. Chloroquine

Chloroquine ang treatment for vivax malaria from Day 0 to 2. At remember, resistant na ang falciparum sa Chloroquine.

*Although P. vivax already has an increasing resistance to Chloroquine.

35
Q

This antimalarial can also be used as a treatment for some inflammatory and connective tissue disease, discoid lupus erythematosus and rheumatoid arthritis.

a. Chloroquine
b. Coartem
c. Tetracycline
d. Quinine

A

a. Chloroquine

It is used as a 2nd line drug to all listed conditions.

36
Q

Biocrystallization of parasitic heme produces what non-toxic compound that protects the Plasmodium from autodigestion?

A

Hemozoin.

  • MOA of chloroquine involves the prevention of the biocrystallization of parasitic heme into hemozoin leading to heme build-up and lysis of the parasite.
37
Q

ADRs of Chloroquine?

A
  • Pruritus common, esp for Africans
  • Nausea
  • vomiting
  • abdominal pain
  • headache
  • anorexia
  • malaise,
  • vision blurring
  • urticaria
  • Rare - hemolysis in G6PD deficiency, impared hearing, confusion, psychosis, seizures, agranulocytosis, exfoliative dermatitis, alopecia, hair bleaching, hypotension, ECG changes such as widen QRS and abnormal T-waves
38
Q

The fixed combination of antifolate drugs Pyrimethamine + Sulfadoxine is also known as:

A

FANSIDAR

39
Q

It is the only tissue schizonticide.

A

PRIMAQUINE.

  • Eradicates exoerythrocytic and gametocytic forms, interrupts transmission of disease.
40
Q

TRUE or FALSE: Primaquine is available only in oral preparations.

A

TRUE

41
Q

Why is a longer treatment course with Tissue Schizonticide after a Blood Schizonticide (ex. Chloroquine) needed for cases of vivax malaria compared to falciparum malaria?

A

P. vivax has a longer tissue stage and therefore requires a longer duration of treatment with a tissue schizonticide (14 days) than for falciparum (1 day) to prevent relapse.

42
Q

ADR’s of Primaquine:

a. GIT distress
b. methemoglobinemia
c. hemolysis in G6PD-deficient patients
d. AOTA
e. NOTA

A

d. AOTA.

Although usually well-tolerated, it may cause GIT distress, pruritus, headaches, methemoglobinemia and hemolysis in G6PD-deficient.

43
Q

Which helminth has infected the most number of people?

a. ASCARIS
b. HOOKWORM
c. TRICHURIS
d. ENTEROBIUS

A

a. ASCARIS

There are about 1.8B Ascaris infections worldwide.

44
Q

The best anti-helminthic drug and usual drug of choice because it has a broad spectrum, it is selectively toxic to the helminth, has local action and poor systemic absorption.

a. MEBENDAZOLE
b. ALBENDAZOLE
c. PYRANTEL EMBONATE
d. NOTA

A

a. ALBENDAZOLE
* Also used for: strongyloidiasis, hydatid disease, neurocystocircosis, cutaneous larva migrans, and intestinal capillariasis.

45
Q

(AMP) Albendazole, Mebendazole or Pyrantel Embonate: Which anthelmintic drug paralyzes the worm by stimulating the nicotinic receptors present at the neuromuscular junctions causing super contraction of muscles followed by depolarization which induces paralysis?

A

Pyrantel Embonate.

Albendazole and Mebendazole are both glucose-uptake inhibitors. Both inhibits microtubule synthesis thus irreversibly impairing glucose uptake and formation of ATP.

46
Q

TRUE or FALSE: Mebendazole must be taken with food.

A

FALSE.

  • Fatty meals increases the absorption and we don’t want to absorb this drug so take it on an empty stomach.
47
Q

Drug of choice for Filariasis and is the only drug available in the Philippines.

A

DIETHYLCARBAMAZINE (DEC)

  • Dose for lymphatic filariasis:

o D1- 50 mg after meals

o D2- 50 mg 3x/day

o D3- 100mg3x/day

o D4- 6mg/kg/day in 3 div. doses

48
Q

Drug of choice for schistosomiasis:

A

PRAZIQUANTEL

MOA: Increases membrane permeability to calcium, causing marked contraction initially and then paralysis of trematode muscles, followed by vacuolization and parasite death.

49
Q

What organism usually serves as an intermediate host for schistosomes?

A

SNAILS!

50
Q

CESTODE and TREMATODE infections are best treated with:

A

PRAZIQUANTEL

CESTODES

  • Taenia saginata
  • Taenia solium
  • Cysticercosis (caused by larval cysts of Taenia solium and treated with Albendazole)
  • Diphyllobotrium latum
  • Echinococcus granulosis (Dog tapeworm: Albendazole is drug of choice)

TREMATODES (flukes):

  • Schistosoma haematobium
  • S. mansoni
  • S. japonicum
  • Paragonimus westermani
  • Drug of choice para sa lahat ng TAEnia at DiphylLOBOTrium (LOBOT and bisaya for pwet) at Schistosoma ay PRAZIQUANTEL. Gamot sa ibang bulate ay probably Albendazole.

[Ther 201] Exam 3 Flo Cluster (2 decks)

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