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Flashcards in Anti-parasitics Deck (91)
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1
Q

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

A
  • 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
Q

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

A
  • Definitive: harbors sexual parasitic stage
  • Intermediate: harbors larval or asexual stage
  • Incidental host: not necessary for parasitic infection
3
Q

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

A
  • Gametogony: sexual development

- Schizogeny: asexual development

4
Q

Where would you use chloroquine, and for what reason?

A

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

5
Q

*Name the 2 best treatments for malarial prevention.

A
  • Mefloquine

- Atovaquine + proguanil

6
Q

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

A

Doxycycline

7
Q

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

In what pt population would you avoid using this?

A

Primaquine

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

8
Q

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

A

Chloroquine

9
Q

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

A

Primaquine (w/chloroquine)

10
Q

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

A

*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
Q

Name the LUMINAL agents used in the treatment of amoebiasis.

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

A
  • Iodoquinol
  • Paromomycin
  • Diloxanide furoate

Add metronidazole

12
Q

What substance does an amoebic liver abscess resemble?

A

Anchovy paste

13
Q

What are the 2 primary tx agents for giardiasis?

What are 2 alternates?

A

Primary: metronidazole, nitazoxanide
Alternate: furazolidone, albendazole

14
Q

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

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

A

Restoration of immune response

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

15
Q

What’s the DOC combo for toxoplasmosis?

A

Pyramethamine + sulfadiazine/clindamycin

16
Q

What are the 2 broad categories of leishmaniasis?

A

Visceral and cutaneous

17
Q

What’s the mainstay for tx of Leishmaniasis?

What else can be used?

A

Na+ Stibogluconate

- Amphotericin B, liposomal amphotericin B, miltefosine

18
Q

What’s the DOC for AFRICAN trypanosomiasis?

What are some other options?

A
  • Suramin (crosses BBB)

- Alt’s: Pentamidine, melarsoprol, eflonithine

19
Q

What’s the DOC for AMERICAN trypanosomiasis?

What’s another option?

A
  • Nifurtimox

- Alt: benznidazole

20
Q

What bug causes Chagas dz?

A

T. cruzi (American trypanosomiasis)

21
Q

What diseases have parasites w/ kinetoplasts?

A

Chagas disease, leishmaniasis, and sleeping sickness

there is a new drug that targets these. prob not on test

22
Q

What is the DOC for neurocystocercosis?

A

Albendazole

23
Q

What’s the DOC for filariasis?

A

Diethylcarbamazine

24
Q

What the DOC for onchocerciasis?

A

Ivermectin

25
Q

What the DOC for strongyloidiasis?

A

Ivermectin

26
Q

What is the major side effect of sodium phosphate?

A

Acute phosphate nephropathy

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

27
Q

Contraindications for Mg citrate and Mg OH?

A

Bowel obstruction, renal failure

28
Q

Which osmotic laxative is used for surgery prep?

A

Polyethylene glycol

29
Q

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

A

Docusate (detergent/surfactant/stool-softener)

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

30
Q

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

A

Lipoid pneumonitis

31
Q

Name the other stimulant laxative we learned about besides senna.

A

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

32
Q

Miralax is a smaller dosed version of what?

A

Polyethylene glycol

33
Q

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

A

Dehydration, electrolyte abnormalities, ischemic colitis

34
Q

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

A
  • Promethazine
  • Sedation

(also includes diphenhydramine, meclizine)

35
Q

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

A

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
Q

What is the MoA for prochlorperazine?

A

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

37
Q

What is torticullis?

What med is it a SE of?

A

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

  • Prochlorperazine
38
Q

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

*When would they be indicated?

A
  • Prednisone
  • Dexamethasone

*Indicated in nausea due to increased intracranial pressure

39
Q

Dronabinol: MoA?

A

(Purified synthetic delta-9-tetrahydrocannabinol)

- Cannabinoid receptor (CB1) agonist. CB1 receptors located throughout CNS.

40
Q

Dronabinol: indications?

A

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

41
Q

Dronabinol: toxicity?

A

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
Q

When is prochlorperazine indicated?

What are it’s side effects similar to?

A

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

Side effects similar to metoclopromide

43
Q

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

A

Chloroquine
Mefloquine
Quinine & quinidine
Primaquine

44
Q

What’s the MoA of atorvaquone?

A

Inhibits parasite mitochondrial electron transport

45
Q

What’s the MoA of doxycycline?

A

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

46
Q

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

A

Quinine/quinidine

47
Q

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

A

Primaquine

48
Q

What are the side effects of chloroquine?

A

Pruritis (African-Americans)

49
Q

What are the side effects of mefloquine?

A

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

50
Q

What are the side effects of atovaquone?

A

GI side effects

51
Q

What are the side effects of doxycycline?

A

Photosensitivity; esophagitis. Risk for vaginal candidasis.

52
Q

What are the side effects of quinine/quinidine?

A

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

53
Q

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

A

Primaquine

also contraindicated in granulocytopenia

54
Q

What’s the MoA of artemisinin?

AKA Quinghausu

A

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

55
Q

What are the side effects of artimisinin?

A

Potential neurotoxcity (ototoxicity) unresolved.

56
Q

Which of the antimalarials are safest for children?
Which are “ok”?
Which are unsafe?

A

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

57
Q

Which of the antimalarials are safest during pregnancy?
Which are “ok”?
Which are unsafe?

A

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

58
Q

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

A

Severe renal failure

59
Q

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

A

Artemisinin

60
Q

When would you consider using doxycycline for malaria?

A

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

61
Q

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

A

Chloroquine

62
Q

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

A

Mefloquine

63
Q

What’s the MoA for metronidazole?

A

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

64
Q

What are the side effects of metronidazole?

A

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

65
Q

What are the side effects of iodoquinol?

A

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

66
Q

What are the side effects of nifurtimax?

A

GI, rash, CNS

67
Q

What are the contraindications for metronidazole?

A

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

68
Q

What are the side effects of albendazole?

A
  • Short term: minimal
  • Longer therapy: elevated aminotransferases, GI effects
    2 day s/p therapy may see inflammation and increased ICP w/neurocystocercosis
69
Q

What are the side effects of mebendazole?

A

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

70
Q

What are the side effects of praziquantel?

A

(Mild) dizziness, HA, drowsiness, abdominal pain

71
Q

What are the side effects of pyrantel pamoate?

A

Mild/transient

72
Q

What are the side effects of ivermectin?

A

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

73
Q

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

A
Albendazole
Praziquantel
Mebendazole
Pyrantel pamoate
Ivermectin
74
Q

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

A

Children under 2

75
Q

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

A

Ocular cysticercosis (inflammation)

76
Q

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

A

Children under 2; liver disease

77
Q

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

A

Co-existing CNS inflammation

78
Q

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

A

Praziquantel

79
Q

Which anti-helminthic interacts w/carbamezapine and dilantin?

A

Mebendazole

80
Q

What are the side effects for H2 blockers?

A

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
Q

How are H2 blockers eliminated?

What about cimetidine?

A

All mostly renal, except cimetidine is hepato-renal.

82
Q

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

A

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

83
Q

How are PPIs eliminated?

A

Hepatic

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

84
Q

Sucralfate: MoA?

A

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

85
Q

Sucralfate: indications?

A

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

86
Q

Sucralfate: side effects?

A

Constipation, dry mouth, nausea, diarrhea

87
Q

How is sucralfate eliminated?

A

Renally

88
Q

Can you give H2 inhibitors w/PPIs?

A

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

89
Q

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

A

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

90
Q

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

A

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

Diarrhea

91
Q

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

A

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.