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Flashcards in Anti-parasitics Deck (91):
1

The treatment goal for protozoa is ___________, while the treatment goal for helminths is ___________.

- Eradication
- Eradication or reduction

Protozoa: complete replication w/in definitive host; illness results from single exposure.

Helminths: life-cycle involves more than definitive host; repeated exposures necessary for disease.

2

What's the difference b/w definitive host, intermediate host, and incidental host?

- Definitive: harbors sexual parasitic stage
- Intermediate: harbors larval or asexual stage
- Incidental host: not necessary for parasitic infection

3

What's the difference b/w gametogony and schizogeny?

- Gametogony: sexual development
- Schizogeny: asexual development

4

Where would you use chloroquine, and for what reason?

Only in areas w/o resistant Plasmodium falciparum (for prevention).

5

*Name the 2 best treatments for malarial prevention.

- Mefloquine
- Atovaquine + proguanil

6

In areas of high multi-drug resistance, what drug would you give to prevent malaria?

Doxycycline

7

For terminal prophylaxis vs. Plasmodium vivax and ovale, what drug would you use?

In what pt population would you avoid using this?

Primaquine

Avoid in G6PD deficiency pts, pregnancy, and granulocytopenics (children 'okay')

8

Assuming no resistance, what's the preferred drug to treat P. falciparum malaria?

Chloroquine

9

What drug combo would you use to treat P. vivax and ovale infections?

Primaquine (w/chloroquine)

10

What defines a "complicated" malarial infection? (not sure if it will be tested)

*Complicated or severe malaria is defined as coma or severely AMS, hypoglycemia, renal failure, parasitemia > 5%, seizures other than 1 short febrile seizure, respiratory distress, shock, etc.

11

Name the LUMINAL agents used in the treatment of amoebiasis.

What should you add if there is colitis or liver abscess?

- Iodoquinol
- Paromomycin
- Diloxanide furoate

Add metronidazole

12

What substance does an amoebic liver abscess resemble?

Anchovy paste

13

What are the 2 primary tx agents for giardiasis?
What are 2 alternates?

Primary: metronidazole, nitazoxanide
Alternate: furazolidone, albendazole

14

What's an important management principle in treating cryptosporidiosis w/HIV?

What's the DOC?
What are some other agents?

Restoration of immune response

DOC: Nitazoxanide (even in moderately immunosuppressed)
Others: Paromomycin, (azithromycin, clarithromycin)

15

What's the DOC combo for toxoplasmosis?

Pyramethamine + sulfadiazine/clindamycin

16

What are the 2 broad categories of leishmaniasis?

Visceral and cutaneous

17

What's the mainstay for tx of Leishmaniasis?
What else can be used?

Na+ Stibogluconate
- Amphotericin B, liposomal amphotericin B, miltefosine

18

What's the DOC for AFRICAN trypanosomiasis?
What are some other options?

*Suramin (crosses BBB)

- Alt's: Pentamidine, melarsoprol, eflonithine

19

What's the DOC for AMERICAN trypanosomiasis?
What's another option?

*Nifurtimox

- Alt: benznidazole

20

What bug causes Chagas dz?

T. cruzi (American trypanosomiasis)

21

What diseases have parasites w/ kinetoplasts?

Chagas disease, leishmaniasis, and sleeping sickness
(there is a new drug that targets these. prob not on test)

22

What is the DOC for neurocystocercosis?

Albendazole

23

What's the DOC for filariasis?

Diethylcarbamazine

24

What the DOC for onchocerciasis?

Ivermectin

25

What the DOC for strongyloidiasis?

Ivermectin

26

What is the major side effect of sodium phosphate?

Acute phosphate nephropathy

Risk factors for nephropathy: old age, renal insufficiency, V depletion, meds (ACEIs/ARBs)

27

Contraindications for Mg citrate and Mg OH?

Bowel obstruction, renal failure

28

Which osmotic laxative is used for surgery prep?

Polyethylene glycol

29

What agent should you prescribe to PREVENT the formation of hard stool?

Docusate (detergent/surfactant/stool-softener)

Glycerin suppositories/enemas would also work, but she calls it a lubricant

30

Why should mineral oil (a lubricant) never be administered orally to sick/debilitated pts?

Lipoid pneumonitis

31

Name the other stimulant laxative we learned about besides senna.

Bisacodyl (unlike senna, doesn't cause melanosis coli)

32

Miralax is a smaller dosed version of what?

Polyethylene glycol

33

What are the possible side effects of magnesium-based osmotic laxatives?

Dehydration, electrolyte abnormalities, ischemic colitis

34

What's the name of the H1 receptor blocker that we should know for the exam?
- What's it's main side-effect?

*Promethazine
- Sedation

(also includes diphenhydramine, meclizine)

35

What is the full MoA for metoclopramide? (2 things)

1) Dopamine receptor antagonist (CTZ/area prostrema).
2) Dopamine receptors inhibit cholinergic smooth muscle stimulation, blockade of this effect = primary prokinetic action, promiting motility of the upper GI tract (increasing pressure in lower esophageal sphincter and increasing gastric emptying)"

36

What is the MoA for prochlorperazine?

Central dopamine receptor antagonist in chemorecetpor trigger zone (CTZ) AKA area prostrema. May peripherally block vagus n.

37

What is torticullis?

What med is it a SE of?

Torticollis is a condition in which the neck muscles cause the head to turn or rotate to the side.

- Prochlorperazine

38

Name 2 corticosteroids that can be used as anti-emetics.

*When would they be indicated?

- Prednisone
- Dexamethasone

*Indicated in nausea due to increased intracranial pressure

39

Dronabinol: MoA?

(Purified synthetic delta-9-tetrahydrocannabinol)
- Cannabinoid receptor (CB1) agonist. CB1 receptors located throughout CNS.

40

Dronabinol: indications?

Breakthrough chemo-induced N/V (ie last resort).

41

Dronabinol: toxicity?

Euphoria, dysphoria, paranoid delusions, cognitive clouding, somnolence, sedation, hypotension.

(Effectiveness: Greater than placebo, similar to phenothiazines.
5HT3 receptor antagonists have greater potency than CB1 agonists.
Narrow therapeutic window.)

42

When is prochlorperazine indicated?

What are it's side effects similar to?

Opioid-related N/V; GI disorders (inflammation/infection, ie gastroenteritis…may block vagal n to CNS)

Side effects similar to metoclopromide

43

What anti-malarias have a MoA of inhibiting heme polymerase, increasing free (toxic) heme?

Chloroquine
Mefloquine
Quinine & quinidine
Primaquine

44

What's the MoA of atorvaquone?

Inhibits parasite mitochondrial electron transport

45

What's the MoA of doxycycline?

A semi-synthetic tetracycline; inhibits protein synthesis in parasite organelles

46

What is the DOC to treat the SEVERE forms of malaria (when chloroquine-resistant)?

Quinine/quinidine

47

Which drug is considered a radical cure for exo-erythrocytic forms of P. vivax and ovale?

Primaquine

48

What are the side effects of chloroquine?

Pruritis (African-Americans)

49

What are the side effects of mefloquine?

*Neuropsychiatric toxicities: seizures, psychosis (less common w/prophylaxis); arrhythmias

50

What are the side effects of atovaquone?

GI side effects

51

What are the side effects of doxycycline?

Photosensitivity; esophagitis. Risk for vaginal candidasis.

52

What are the side effects of quinine/quinidine?

*Cinchonism (tinnutus, HA, nausea, dizziness, flushing, visual disturbances), hypoglycemia, blackwater fever,

53

Which anti-malarial can cause hemolysis in the G6PG deficient?

Primaquine
(also contraindicated in granulocytopenia)

54

What's the MoA of artemisinin?

(AKA Quinghausu)

Binds iron in malaria pigment producing free radicals. *Rapidly acting schizonticide.

55

What are the side effects of artimisinin?

Potential neurotoxcity (ototoxicity) unresolved.

56

Which of the antimalarials are safest for children?
Which are "ok"?
Which are unsafe?

Safe: chloroquine, mefloquine
Okay: quinine/quinidine, primaquine
Unsafe: atovaquone, doxycycline

57

Which of the antimalarials are safest during pregnancy?
Which are "ok"?
Which are unsafe?

Safe: chloroquine
Okay: mefloquine (prophylaxis), quinine/quinidine (but causes contractions 3rd trimester)
Unsafe: mefloquine (tx), atovaquone (unless >5kg), doxycycline, primaquine

58

Atovaquone:
Besides being not okay in children <5kg, not okay during pregnancy unless benefit outweights risk (category C), atovaquone is also contraindicated in _______________.

Severe renal failure

59

Which anti-malarial is probably ok in children and pregnancy, but not approved in the US?

Artemisinin

60

When would you consider using doxycycline for malaria?

*Used for chemo-prophylaxis in areas of high mefloquine resistance (eg SE Asia).

61

*What is the DOC for malarial infection if resistance is not a concern?

Chloroquine

62

*What is the DOC for chemoprophylaxis in most regions (esp. if chloroquine-resistant), but is not recommended for tx of severe malaria?

Mefloquine

63

What's the MoA for metronidazole?

Ferrodoxin-linked processes reduce nitro group to a product that is lethal vs. anaerobic organisms.

64

What are the side effects of metronidazole?

N/V, metallic taste, disulfuram-like rxn (w/etoh)

65

What are the side effects of iodoquinol?

N/V, neurotoxicity (all rare at recommended doses)

66

What are the side effects of nifurtimax?

GI, rash, CNS

67

What are the contraindications for metronidazole?

Interacts w/anti-coagulants, alcohol (used like antabuse), anticonvulsants

68

What are the side effects of albendazole?

- Short term: minimal
- Longer therapy: elevated aminotransferases, GI effects
2 day s/p therapy may see inflammation and increased ICP w/neurocystocercosis

69

What are the side effects of mebendazole?

Minimal GI to neutropenia and hepatic with long term therapy; hypersensitivity

70

What are the side effects of praziquantel?

(Mild) dizziness, HA, drowsiness, abdominal pain

71

What are the side effects of pyrantel pamoate?

Mild/transient

72

What are the side effects of ivermectin?

(Mild) hypersensitivity from worm death. Mazotti reaction (fever, HA's, dizziness…)* – severe in onchocerciasis.

73

Which of the anti-helminthics are contraindicated in pregnancy and GI tract ulcers?

Albendazole
Praziquantel
Mebendazole
Pyrantel pamoate
Ivermectin

74

Besides being contraindicated in pregnancy and GI ulcers, when else is mebendazole contraindicated?

Children under 2

75

Besides being contraindicated in pregnancy and GI ulcers, when else is praziquantel contraindicated?

Ocular cysticercosis (inflammation)

76

Besides being contraindicated in pregnancy and GI ulcers, when else is pyrantel pamoate contraindicated?

Children under 2; liver disease

77

Besides being contraindicated in pregnancy and GI ulcers, when else is ivermectin contraindicated?

Co-existing CNS inflammation

78

Which anti-helminthic has decreased bioavailability w/corticosteroid therapy?

Praziquantel

79

Which anti-helminthic interacts w/carbamezapine and dilantin?

Mebendazole

80

What are the side effects for H2 blockers?

Hematopoietic and immune effects (B12 deficiency and Idiosyncratic myelosuppression); CNS (confusion, agitation); Hepatic effects (metabolized by cytochrome P450 and can cause drug interactions); Cardiac effects ([Brachycardia, hypotension due to increased vagal?], IV; cardiac toxicity, oral)

Cimetidine only: Inhibits CYP450; gynecomastia, impotence, elevated PRL (galactorrhea); mild increase in creatinine."

81

How are H2 blockers eliminated?
What about cimetidine?

All mostly renal, except cimetidine is hepato-renal.

82

According to Hoppensteadt, what are the side effects of PPIs?

Few (< 3%), generally mild: diarrhea, headache, drowsiness, muscle pain and constipation

83

How are PPIs eliminated?

Hepatic

(pro-drugs, activated in acidic compartment, then form disulfide bind w/p+ pump)

84

Sucralfate: MoA?

Mucosal protective agent. Sulphated polysaccharide complexed with Al OH. Binds necrotic tissue to create barrier between the gastric contents and the mucosa.

85

Sucralfate: indications?

Effective at treating duodenal ulcers (not NSAID related) and the suppression of H. Pylori.

86

Sucralfate: side effects?

Constipation, dry mouth, nausea, diarrhea

87

How is sucralfate eliminated?

Renally

88

Can you give H2 inhibitors w/PPIs?

H2 antagonists should not be given simultaneously with PPIs because they reduce the efficacy of the PPIs.

89

What are antacids made of, and how do they work?

Neutralizes gastric and reduces delivery to the duodenum. Contain compounds such as Na HCO3, Al OH, Mg CO3 or Mg OH

90

Absorption of large amounts of antacids can lead to __________________.
What side effect is a/w antacids that contain Mg?

Milk-alkali syndrome (hypercalcemia, alkalosis, renal impairment)

Diarrhea

91

Compare and contrast the indications for H2 blockers vs. PPIs.

H2 blocks: GERD; gastric & duodenal ulcers (2nd line to PPI)

PPIs: GERD (erosive and non-erosive); duodenal and gastric ulcers, 1st-line (preferred for NSAID-induced ulcers); Zollinger-Ellison syndrome (gastrinoma); role in H. pylori tx.