Antiparasitic-Table 1 Flashcards Preview

Pharm3- fixed > Antiparasitic-Table 1 > Flashcards

Flashcards in Antiparasitic-Table 1 Deck (150):
1

What is the definition of symbiosis?

relationship between two species for the purpose of obtaining food or habitat

2

What is parasitism?

type of symbiotic relationship in which one species, the host, is injured by the activities of the other

3

What 2 things is injury dependent on?

Parasite load and immunologic competence of host

4

What are the protozoal diseases?

Malaria
Giardiasis (intestinal)
Amebiasis (intestinal)

5

What are the Helminth diseases?

Necatoriasis (hookworm)
Enterobiasis (pinworm)
Ascariasis (roundworm)
Neurocysticercosis (tapeworm)

6

What are the 3 major potential targets for antiparasitic chemotherapy?

-Unique enzymes found only in the parasite
-Enzymes found in the both host and parasite but indispensible only to the parasite
-Common biochemical functions found in both parasite and host but with different pharmacologic properties

7

What are the protozoal tx for malaria?

-Chloroquine, hydroxychloroquine, quinine, Mefloquine, artemisinin, pyrimethemine
-Primaquine
-Doxycycline

8

What is the protozoal tx for giardiasis?

Metronidazole

9

What is the protozoal tx for amebiasis?

-Paromomycin
-Diloxamide
-Metronidazole

10

What drugs are effective against malaria in the tissue? RBC? Gametocytes?

--primaquine, doxycycline
--chloroquine, quinine, mefloquine
--primaquine

11

What is the chloroquine chemoprophylaxis for malaria?

Chloroquine 500mg (300mg of base) po weekly OR
Hydroxychloroquine 400mg (310mg of base) po weekly

12

When is the chloroquine chemoprophylaxis used?

in areas where P. falciparum is susceptible

13

What is the chloroquine chemoprophylaxis active against?

erythrocytic forms of malaria

14

When should tx with the chloroquine chemoprophylaxis be initiated and how long should it be continued?

1 week before exposure and 4 weeks after leaving endemic area

15

What is the MOA the chloroquine chemoprophylaxis?

causes membrane lysis of both parasite and RBC

16

What are the ADRs of cholorquine?

Dyspepsia, vertigo, insomnia, retinal toxicity (long duration)
Discoloration of nail beds and mucous membranes with chronic administration

17

Is chloroquine safe in pregnancy?

Yes but not hydroxychloroquine

18

What is the mefloquine prophylaxis? When is it used?

Mefloquine 250mg po weekly
Used in areas of chloroquine resistance

19

What forms of malaria is mefloquine active against?

erythrocytic forms of malaria

20

What should the mefloquine prophylaxis be initiaited and how long should it be continued?

1 week before exposure (2-3 weeks is preferable) and continue for 4 weeks after leaving malaria-endemic area

21

What are the ADRs of mefloquine?

dyspepsia, vertigo, insomnia, vivid dreams, SZs, depression, suicidal ideation

22

What pts should you not prescribe mefloquine to?

Recent HX of depression, GAD, schizophrenia, psychosis or convulsions
Performing activities requiring fine coordination and spatial discrimination (eg. Pilots, machine operators)

23

Is mefloquine safe in preggos?

Yes

24

What is the atovaquone and proguanil prophylaxis?

250mg atovaquone/100mg proguanil: 1 tab po daily

25

When should atovaquone and proguanil prophylaxis be initiated and how long should it be continued?

1 day prior and continue for 1 week after leaving malaria-endemic area

26

What are the ADRs of atovaquone and proguanil ?

well tolerated, abdominal pain, N/V, HA, increased LFTs

27

When is atovaquone and proguanil CI?

Pregnant women (no data)
Patients with severe renal dysfunction (Clcr

28

What is the doxycycline chemoprophylaxis?

100mg po daily (very inexpensive)

29

When should doxycycline chemoprophylaxis be initiated and how long should it be continued?

1 day prior to exposure and continue for 4 weeks after leaving malaria-endemic area

30

What is doxy effective against?

erythrocytic forms of malaria
Not effective as sole agent in treatment

31

What are the ADRs of doxy?

dyspepsia and esophagitis, vaginal candidiasis, photosensitivity

32

When is doxy CI?

Pregnant women
Children

33

What is the tx of malaria guided by?

-Infecting species and drug susceptibility determined by geographic area
-Patient status

34

Which malarial organisms have reported resistance?

P. falciparum and P. vivax

35

Which malarial organism can cause rapidly progressive severe illness or death?

P. falciparum

36

Which organisms have hypnozoite forms that may remain dormant in the liver and need tx?

P. ovale and P. vivax

37

What Is the tx for uncomplicated adult malaria that is chloroquine sensitive?

Chloroquine-sensitive
--Chloroquine (Blood Schizontocide)
--1000mg followed by 500mg 6hr later, then again at day 2 and 3
OR
--Hydroxychloroquine
--800mg followed by 400mg 6hr later, then again at day 2 and 3

38

How is P. vivax or P. ovale malaria tx in uncomplicated adults?

Above and Add primaquine 30mg po daily x 14 days (avoid in G6PD deficiency)

39

What does primaquine do?

Tissue Schizonticide---Eradicates primary exoerythrocytic forms of P. falciparum and P. vivax and secondary exoerythrocytic forms of recurring P. vivax and P. ovale

40

When is primaquine not effective?

Against the erythrocytic stage…cant use as monotherapy

41

What are the ADRs of primaquine?

-Well tolerated = GI and HA most common
-Rare = agranulocytosis and cardiac arrhythmias
-G6PD deficiency => hemolysis
---Patients should be tested before given

42

What is the tx for uncomplicated malaria in adults with resistance?

Mefloquine
750mg po x 1 then 500mg 6-12hrs later
OR
Atovaquone-proguanil
4 tabs po daily x 3 days
OR
Quinine + Doxycycline
Quinine 650mg TID x 3-7 days
Doxycycline 100mg BID x 7 days

43

What is quinine?

A blood schizonticide active against all 4 species of plasmodium

44

What is the MOA of quinine?

interferes with heme polymerization resulting in death

45

What are the ADRs of quinine?

-Cinchonism = tinnitus, HA, dizziness, visual disturbances, nausea (reversible)
-Hypersensitivity and blood dyscrasias (hemolytic anemia)
-Fetotoxic- no preggos

46

When is quinine used?

Reserved for severe infestations and for strains resistant to chloroquine

47

What are the quinine drug interactions?

Potentiates neuromuscular blocking agents
Increases digoxin level
Decreased absorption with Al antacids

48

What is the definition of severe malaria?

Impaired consciousness/coma/convulsions
Severe normocytic anemia
Renal failure
Pulmonary edema
ARDS
Circulatory shock
Spontaneous bleeding
Jaundice
High parasitemia (>5%)

49

What organism typically causes severe malaria?

P. falciparum

50

What is the tx for severe malaria?

Quinidine gluconate 600mg IV q12H
PLUS
Doxycycline 100mg IV q12H x 3-7 days

51

What is the resolution time for severe tx?

Fever should break within the first 48 hours and blood should clear of parasites within 5 days

52

Does malarial infection produce immunity?

NO

53

What is artemisinin?

A blood schizonticide used to tx severe multidrug resistant P. falciparum

54

What is the MOA of artemisinin?

free radical production within food vacuole following cleavage of drug’s endoperoxide bridge by heme iron in RBC
Covalently binds and damages malarial proteins

55

How is artemisinin distributed?

PO,IV, rectal

56

What are the ADRs of artemisinin?

Overall safe, N/V/D
High doses neurotoxic and QT prolongation

57

What is pyrimethamine?

Antifolate agent for blood schizonticide and sporontocide

58

What is pyrimethamine effective against?

P. faciparum

59

What are the ADRs of pyrimethamine?

Megaloblastic anemia
---Folic acid replacement
---Reverse with leucovorin

60

What is the first line tx for Giardia in people >/= 8 years old?

metronidazole (Flagyl) 250mg po TID x 7 days

61

What are the ADRs of metro?

abdominal discomfort, N/V, metallic taste, disulfiram rxn with ETOH

62

What is an alternative therapy for giardia?

Nitazoxanide 500mg po BID x 3 days

63

What are the ADRs of Nitazoxanide?

abdominal pain, N/V/D, HA

64

What does the drug tx for amebiasis depend on?

Clinical presentation! This depends mainly on location
Intestinal= asymptomatic, dysentery, or colitis
Extraintestinal= primaryily liver abscess

65

How are asymptomatic patients tx for amebiasis?

Tx with luminal agents only- non absorbable agents

66

How are all symptomatic patients tx?

With a luminal agent plus a tissue amebicide

67

What are the drug choices for asymptomatic or luminal amebiasis?

Paromomycin 500mg TID x 7 days- use if preggo
Diloxamide 500mg TID x 10 days

68

What is the tx for severe intestinal dz or liver abscess?

Aspirate and drain
The metro 750mg po TID x 10 days followed by luminal course then reassess the abscess with imaging 3 mo later

69

When are luminal agents effective?

To tx the asymptomatic colonization state or following tx of invasive dz

70

What are the luminal amebicides?

Iodoquinol, Diloxanide, Paromomycin

71

What is iodoquinol effective against?

E. histolytica luminal trophozoites and cyst forms only

72

What are the ADRs of iodoquinol?

GI most common (diarrhea)
Optic neuritis, optic nerve atrophy (rare)

73

How long does a pt need to be tx with iodoquinol?

650mg po TID x 20 days

74

Pts intoletant to what should not receive iodoquinol. Why?

IODINE- drug molecule contains iodine, nIncreases body iodine content which may persist for months => mild thyroid enlargement

75

What are signs of iodine toxicity to look for in pts taking iodoquinol?

Itching, rash, and fever

76

What is diloxanide used to tx?

asymptomatic shedders of cysts; not available in US or Canada

77

What are the ADRs of diloxanide?

Flatulence, dry mouth, pruritis, urticaria

78

When is diolxanide CI?

Preggo and

79

What is paromomycin?

Aminoglycoside antibiotic

80

How does paromomycin work?

cell membrane leakage
decreases normal flora which is source of food for amebas

81

What are the ADRs of paromoycin?

GI distress and diarrhea

82

What is the mixed Amebicide?

metronidazole

83

When is metro the DOC?

For extraluminal amebiasis- kills tophozoites but not cysts

84

What is the MOA of metro?

nitro group of metronidazole serves as electron acceptor, forming reduced cytotoxic cmpd that bind proteins and DNAdeath

85

When should metro be adjusted?

In severe liver dz

86

What is the regimen for mild- mod dysentery?

flagyl + paromomycin or iodoquinol to clear cysts

87

What is the regimine for severe or extraintestinal infection?

flagyl + paromomycin

88

What are the ADRs of metro…againt?

Most common = nausea, HA, paresthesias, metallic taste
--GI side effects decreased by giving with food
--CNS side effects include paresthesias
Disulfiram-like reaction
---May cause N,V, flushing if alcohol is ingested during therapy- most unpleasant. I do not recommend tequila and metro!

89

What are the systemic/tissue amebicides?

Chloroquine, emetine, and dehydroemetine

90

When is chloroquine used in amebiasis?

in combo with metronidazole and diloxanide furoate to tx and prevent amebic liver abscesses

91

When are emetine and dehydroemetine used?

to treat liver abscesses unresponsive to flagyl

92

How long is the duration of tx for emetine?

Limited to 10 days d/t toxicity- dehydroeme is less toxic

93

How long is the half life of emetine?

5 day, 1 IM injection lasts one month

94

What are the ADRS of emetine?

Injection site pain, transient nausea, neuromuscular weakness, dizziness, rash, cardiotoxicity- arrhythmias, CHF

95

What worms are parasites?

Necatoriasis (hookworm)
Enterobiasis (pinworm)
Ascariasis (roundworm)
Neurocysticercosis (tapeworm)

96

What do anthelmintic drugs need to do in order to be effective?

Penetrate the cuticle of the worm
Or gain access to its alimentary tract

97

How do anthelmintic drugs work?

Damaging or killing the worm directly.
Paralysing the worm
Damaging the cuticle of the worm so that host defences, such as digestion and immune rejection, can work.
Interfering w/worm metabolism.

98

What are the anthelmintic drugs?

Mebendazole
Albendazole

99

What is the tx for Enterobiasis (pinworm)?

Mebendazole 100mg x 1, may repeat in 14 days
For all persons > 2 years

100

What is the alternative tx for pinworm?

Albendazole 400mg x 1, repeat in 14 days
For all persons > 2 years

101

What re the ADRs for Albendazole?

abdominal pain, N/V, Stevens-Johnson syndrome, hematologic effects (pancytopenia, thrombocytopenia, leukopenia, aplastic anemia), hepatotoxicity

102

How is necatoriasis (hookworm) tx?

Mebendazole 100mg po BID x 3 days
OR
Albendazole 400mg po x 1
(For all persons > 2 years)

103

How is ascariasis (roundworm) tx?

Mebendazole 100mg po BID x 3 days
OR
Albendazole 400mg po x 1
For all persons > 2 years…if there is a severe obstruction surgery is needed

104

Why is it important to have caution when tx neurocysticercosis ( tapeworm)?

Sudden destruction of parasites may trigger inflammatory response and seizures

105

Does elimination of the parasite in tapeworm mean there will be neuro improvement?

NO

106

What are the options for tx tapeworm?

Surgery
Anticonvulsants
Albendazole 400mg BID +/- dexamethasone 6mg daily for 8-30 days

107

What is mebendazole?

Broad spectrum antihelminthic

108

How is mebendazole prescribed?

100mg x1 and repeat in 2 weeks

109

How does menendazole work?

Irreversibly inhibits glucose uptake in susceptible nematodes; also interferes with assembly of microtubules

110

What is mebendazole used to tx?

Whipworm, roundworm, hookworms, pinworms

111

How is the efficacy of mebendazole increased?

By chewing tablets- poorly absorbed

112

What are the most common ADRs of mebendazole?

Abdominal discomfort and diarrhea

113

When is mebendazole CI?

pregnant patients in first trimester, in children

114

What is albendazole?

Broad spec antihelminthic that enters the CNS and cysts and is larvicidal

115

How is albendazole administered?

On an empty stomach for luminal parasites and with a fatty meal for extraluminal dz

116

Short term albendazole has few ADRS( hA/N). what is the risk with high doses or long term therapy?

Hepatotoxicity, pancytopenia, inflammation in CNS HA, voniting, hyperthermia, mental changes, convulsion

117

What should you do if giving high or long doses of albendazole to your pt?

baseline LFT’s and a CBC every 2 weeks

118

When is albendazole CI?

pregnant patients in first trimester, in children

119

What is the MOA of niclosamide?

Inhibition of mitochondrial anaerobic phosphorylation of ADP no energy

120

What is the ROA of niclosamide?

PO- little is absorbed from the GI

121

When is niclosamide indicated?

Tapeworm infestation- Cestodes

122

What are the ADRs of niclosamine?

Very little since not absorbed from GI
Some mild GI disturbance

123

What do you need to give your pt prior to niclosamide?

Laxatives to purge the OVA

124

What is pyrantel pamoate used for?

Roundworms, pinworms, hookworms
Poorly absorbed and used only for intestinal parasites

125

How does pyrantel pamoate work?

Acts as a depolarizing neuromuscular blocker inducing worm paralysis

126

What are the ADRs of pyrantel pamoate?

mild, infrequent and transient = most common = GI (N/V/D)

127

Is pyrantel pamoate available OTC?

Yes as Pin-Rid or Pin-X

128

What is pyrantel pamoate not active against?

Migratory stage and ova

129

What are the CI to pyrantel pamoate?

pregnant patients in first trimester, in children

130

What is the MOA of praziquantel?

Increases cell membrane permeability to calcium causing paralysis, dislodgement and death

131

When is praziquantel effective?

wide variety of nematode, trematode and cestode infections

132

How is praziquantel absorbed and excreted?

PO and urine/bile

133

What should you admin to a pt with tapeworms following praziquantel?

of a purgative- dead worms may release embryos that may mature and become infectious

134

How long should praziquantel therapy be prescribed for?

ONE DAY

135

What should your pts be educated about when taking praziquantel?

Should be taken after meals with full glass of water and never chewed

136

What are the most frequent ADRs of praxiquantel?

drowsiness, dizziness, HA, GI upset – appear within 24 hours and go away in the next 24-48

137

Which drugs may interact with praziquantel and cause tx failure?

anticonvulsants

138

Should praziquantel be taken when preggo?

Nope

139

What is the MOA of thiabendazole?

affects microtubular aggregation

140

What is thiabendazole active against?

threadworms, cutaneous larva migrans and early stages of trichinosis (nematodes)

141

What are the ADRs of thiabendazole?

N/V, anorexia, dizziness
Erythema multiforme, SJSfatalities

142

When is thiabendazole CI?

Preggos

143

What is diethylcarbamazine used to tx?

filariasis (elephantiasis) by immobilizing microfilariae thus susceptible to host defenses
Combine with abendazole

144

What are the ADRs of diethylcarbamazine caused by?

host rxn to killed organisms
Severity related to parasite load…fever, malaise, rash, myalgias, arthralgias, HA, leukocytosis tx with steroids, antihistamines

145

What is the causative organism in onchocerciasis? What carries it?

Onchocerca volvulus
Black fly
Microfiliaria(offspring) cause the actual dz

146

What are the symptoms of onchocerciasis ( river blindness)?

Severe itching, subcutaneous nodules, ocular lesions often resulting in blindness (blindness due to years of assault)

147

What is the tx for river blindness?

Ivermectin- can also use against scabies and threadworm

148

How often should ivermectin be used?

Tx once yearly until the adult worms are dead

149

What is the ADR of ivermectin?

Allergic/inflammatory response: Mazotti-like reaction (fever, HA, dizziness, somnolence, hypotension, arthralgia, edema, lymphadenopathy, ocular damage, rash, pruritis, synovitis)

150

When is ivermectin CI?

Preggo