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Pharm Block 4 > Anti-protozoals > Flashcards

Anti-protozoals Flashcards

1
Q

What rapid-acting drugs are used to treat parasites in erythrocytic stage (blood schizontocidal agents)?

A

Chloroquine, Primaquine, Atremisinin

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2
Q

What slow-acting drugs are used to treat parasites in erythrocytic stage (blood schizontocidal agents)?

A

Proguanil, Pyrimethamine-sulfadoxine, Doxycycline (always in combination with fast acting)

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3
Q

What drugs are used to treat parasites in pre-erythrocytic stage and in latent forms known as hypnozoites (tissue schizontocidal agents)?

A

Primaquine

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4
Q

What drugs are used to treat parasites by killing gametes in the blood (gametocidal agents)?

A

chloroquine, primaquine, atrmisinin

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5
Q

What is achieved by attacking the parasite at various stages of its life cycle?

A
  1. To prevent and treat clinical attack of malaria
  2. To eradicate parasite from patient’s body
  3. To reduce human reservoir of infection – cut down transmission to mosquito
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6
Q

Chloroquine is Active against all species of plasmodia (gametocidal) for all except _____.

A

Falciparum

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7
Q

Chloroquine cannnot be used to prevent relapse in _____.

A

vivax malaria

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8
Q

Describe the PK of chloroquine.

A

It gets accumulated in several tissues (high volume of distribution, > 12 L)

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9
Q

Which drug has the ADR of ocular toxicity and why?

A

Cholorquine, selective accumulation in the retina

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10
Q

What is the MOA of chloroquine?

A

Blocks the plasmodium conversion of Fe3+-bound heme (toxic) to hemozoin (non-toxic) after digestion of Hb (occuring inside parasitic vacuole).

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11
Q

What is the drug of choice for the clinical cure of vivax malaria when there is no resistance?

A

Chloroquine

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12
Q

What are the uses of Chloroquine (MALARIA)?

A 
Malaria
Amoebiasis (extraintestinal / hepatic)
Lepra
RA (hydroxychloroquine)
Infectious mononucleosis
Autoimmune disorder (Discoid lupus erythematosus- DLE)
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13
Q

What is the triad of dose-related ADRs with quinine?

A
  1. Cinchonism (tinnitus, high-tone deafness, visual disturbances, headache, dysphoria, nausea, vomiting, and postural hypotension)
  2. Hypoglycemia
  3. Hypotension (precautions)
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14
Q

What are two severe ADRs of quinine?

A

Prolonged Q-T

G-6PD deficiency hemolysis

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15
Q

What is the MOA of artemisinin?

A
  1. Interact with heme in the parasite, release of highly reactive free radicals
  2. Bind to membrane proteins; damages endoplasmic reticulum (inhibits parasite Ca2+ ATPase)
  3. Lysis of parasite
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16
Q

What are the oral forms of artemisinin?

A

Dihydro-artemisinin, artesunate, artemether

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17
Q

Artemisinin is drug of choice for what two conditions?

A

Cerebral malaria and complicated malaria

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18
Q

*****If give anti-folate with another bone marrow suppression drug then what ADR can occur?

A

Neutropenia

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19
Q

What is the MOA of Sulfadoxine?

A

Structural analogs of PABA-compete with PABA for dihydropteroate synthetase (first step)

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20
Q

What is the MOA of Pyrimethamine?

A

Inhibits folate biosynthesis –high affinity inhibition of plasmodial DHFR / Dihydrofolate reductase (third step)

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21
Q

What combination of anti-folates is used for treatment of chloroquine resistant P. falciparum and why?

A

sulfadoxine+ pyrimethamine acts as slow acting blood schizonticidal and provide sequential blockade

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22
Q

Which anti-folate is used for drug sensitive P. falciparum and P. vivax and what is its MOA?

A

Proguanil, inhibits dihydrofolate reductase

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23
Q

What is the MOA of atovaquone?

A

inhibits malarial cytochrome bc1 in the mitochondrial electron transport chain→ disrupts mitochondrial membrane potential

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24
Q

What are the targets of atovaquone?

A

both tissue and RBC schizonts

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25
Q

What combination of anti-protozoals is used for for treatment of uncomplicated malaria and chemoprophylaxis, alternate therapy for P. jiroveci infection( lower efficacy)?

A

Malarone (atovaquone + proguanil)

26
Q

What is the MOA of primaquine?

A

Produce ROS causing cellular oxidative damage

27
Q

What stage of parasite does primaquine work on and what kind of activity does it have?

A

Tissue schizontocide for all 4 species of plasmodia (primary and latent forms, i.e. hypnozites), marked gametocidal activity

28
Q

Which anti-protozoal is used as a radical cure (to prevent relapse by eliminating hypnozoites) given concurrently or after clinical cure (after G6PD status known)?

A

Primaquine

29
Q

How do you give primaquine for P. vivax?

A

Once a day for 14 days

30
Q

How do you give primaquine for P. falciparum and what is its importance?

A

Radical cure (to prevent relapse by eliminating hypnozoites) given concurrently or after clinical cure (after G6PD status known)

31
Q

The combination of _____ and _____ is an alternative regimen for the treatment of pneumocystosis (caused by Pneumocystis jiroveci)?

A

clindamycin, primaquine

32
Q

When is primaquine used in contradicted and why?

A

G6PD deficiency, pregnancy and infants, granulocytopenia, concurrently with BM depressants, bc rarely ADR / can cause BM depression

33
Q

***** Interrupt the G6PD enzyme assay results: <20% = _____, 40%-60% = _____, 70% - 90% = _____. When can you not use primaquine?

A

normal, mild G6PD/heterozygous, severe G6PD = and CANNOT give drug

34
Q

What is the treatment of malaria caused by P. vivax?

A

Chloroquine for clinical cure + Primaquine (14 days) to prevent relapse (radical cure)

35
Q

What is meant by the term “radical cure” when treating malaria?

A

attack exo-erythrocytic stage (hypnozoite) to achieve total eradication of parasite from patient’s body (tissue form)

36
Q

*****What is the treatment used as a clinical cure for malaria caused by P. falciparum?

A

Artemisinin Combination Therapy + + primaquine (single dose -to prevent transmission of malaria only)–> choose the answer ACT as Rx even if primaquine is there!!

37
Q

What is the treatment for severe (complicated) malaria?

A

Artemisinin derivatives –or- Quinine, parenteral route

38
Q

How do you treat malaria in pregnancy?

A

1st trimester : Quinine for 7 days, followed by area specific ACT in 2nd and 3rd trimester OR Clindamycin–> remember do NOT give primaquine

39
Q

Term for Use of drugs to prevent infection, rather than for treatment of malaria

A

Chemoprophylaxis

40
Q

When is chemoprophylaxis recommended?

A

For travellers, migrant workers and military personnel exposed to malaria in highly endemic areas

41
Q

Which anti-malarial is not recommended as prophylaxis in highly endemic areas due to high recurrence rate and chance of resistance?

A

Primaquine

42
Q

What anti-malarial is DOC for chemoprophylaxis on trips > 6 wks. long and what dose would you give?

A

Mefloquine, Once a week, started 3-4 weeks earlier, continued for 4 weeks after return

43
Q

What anti-malarial is DOC for chemoprophylaxis on trips 1 wk. to 6 wks. long and what dose would you give?

A

Doxocycline, Once a day, started 1-2 days earlier, continued for 4 weeks after return

44
Q

What anti-malarial is DOC for chemoprophylaxis on trips < 7 days long and what dose would you give?

A

Atovaquone/proguanil (Malarone), Once a day, started 1-2 days earlier, continued for 7 days after trip

45
Q

What is the drug therapy for Chloroquine sensitive P. falciparum and malaria?

A

Chloroquine

46
Q

What is the drug therapy for P. Vivax and ovale?

A

Chloroquine, Primaquine

47
Q

What is the drug therapy for uncomplicated infections with chloroquine resistant P falciparum?

A

Coartem (Artemether+lumefantrine)

48
Q

What is the alternative drug therapy for uncomplicated infections with chloroquine resistant P falciparum?

A 
Malarone
OR
Mefloquine
OR
Quinine sulfate
49
Q

What is the drug therapy for severe or complicated infections with P falciparum?

A

Artesunate; follow with doxycycline or clindamycin or coartem or mefloquine

50
Q

What is the alternative drug therapy for severe or complicated infections with P falciparum?

A 
Artemether; follow with artesunate 
OR
Quinidine gluconate
OR
Quinine dihydrochloride
51
Q

What are the luminal amoebicides act on the parasite in the lumen of the bowel?

A

tetracyclines and iodoquinol

52
Q

What are the systemic or tissue amoebicides teffective against amoebas in the intestinal wall and liver?

A

Metronidazole, Tinidazole, chloroquine (know these!)

53
Q

What are the three main reasion chloroquine is used in combination with metronidazole and diloxanide furoate?

A
  1. To treat and prevent amebic liver abscesses
  2. Eliminates trophozoites in liver abscesses
  3. Not useful in treating luminal amebiasis
54
Q

What are the ADRs of Metronidazole?

A
  1. bitter metallic taste
  2. disulfiram-like effect
  3. potentiates anticoagulant effect of warfarin causing bleeding
  4. potentiates lithium toxicity (polyuria, dilute urine, and can clear faster so have mania/psychotic symptoms manifest sooner)
55
Q

Metonidazole is used for _____ and _____.

A

Giardiasis (Giardia lamblia), Trichomoniasis (Trichomonas vaginalis)

56
Q

What is the preferred combination to treat Toxoplasmosis (Toxoplasma gondii)?

A

Pyrimethamine and Sulfadiazine +folinic acid

57
Q

When a patient is diagnosed with _____, both sexual partners are treated simultaneously with Metronidazole.

A

Trichomoniasis (Trichomonas vaginalis)

58
Q

What are the ADRs of the broad spectrum anti-protozoal pentamidine used in Pneumocystosis (PCP), sleeping sickness (African trypanosomiasis), and leishmaniasis?

A

Hypoglycemia (5-7 days after use due to insulin release) for couple weeks, followed by hyperglycemia insulin resistance in some cases (because of acute pancreatitis)
Nephrotoxic
Acute pancreatitis

59
Q

*****How would you treat a traveling soldier with non-healing ulcer on forearms and / or face (any exposed area) transferred by a sandfly?

A

Sodium stibogluconate (pentavalent antimonials prodrug to treat Leishmaniasis)

60
Q

Sleeping sickness aka African trypanosomiasis is caused by _____ transmitted by the _____.

A

Trypanosoma brucei, tsetse fly

61
Q

What is the treatment for the first stage of sleeping sickness aka African trypanosomiasis in which there is hemolysis and lymphonode enlargement?

A

suramin, eflornithine (ornithine decarboxylase inhibitor)

62
Q

What is the treatment for the second / late stage of sleeping sickness aka African trypanosomiasis in which there is CNS involvement and sleeping disturbances?

A

melarsoprol (arsenical, arsenic use to be used for bed bugs)

Pharm Block 4 (21 decks)

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