Anti-parasitic agents

Question 1

Chloroquine

Answer 1

Prophylaxis and Treatment

Stage: Schizonticidal in blood to all species
-not active against erythrocytic parasites

MOA: :inhibit heme polymerase; increase free heme; toxic to parasites

Resistance: P falciparum-wide spread resistance

ADR: pruritus

Question 2

Mefloquine
(derivative of chloroquine)

SIDE EFFECT

Answer 2

Prophylaxis(**Areas of chloroquine resistant falciparum) and treatment

Stage: schizonticidal in blood

MOA:inhibit heme polymerase; increase free heme; toxic to parasites

Side effects: neuropsychiatric toxicities (seizures, psychosis) -black box warning
-rare-arrhythmias

Drug interaction quinine

Question 3

Atovaquone (combination with proguanil)

Answer 3

Prophylaxis (better tolerated than mefloquine) and treatment

Stage: RBC schizont
Hypnozoite of P. falcip(dont confuse this its not saying ovale and vivax)

MOA: inhibits parasite mitochondrial electron transport
-need proguanil so it doesn’t develop quick resistance

Preg unknown

Question 4

Doxycycline

a semisynthetic tetracycline

Answer 4

DOC: prophylaxis against mefloquine-res. P falciparum
(i.e. travelers to border areas in thailand)

Treatment and Prophylaxis
MOA: protein synthesis inhibition

Stage: RBC schizont

Not in children or preg!

Question 5

Primaquine

Answer 5

***used to treat exoerythrocytic forms of vivax and ovale

MOA:
similar to chloroquine
Stage:
Hypnozoite 
Gametocyte

Contraindications: granulocytopenia

Relative Contraindications:
**G6PD deficiency

Question 6

Artemisinin

Answer 6

Stage: 
rapidly acting schizonticide ****
Gametocyte
-second agent used to prevent recrudescence
ACT: artemisinin combination therapy

MOA: toxic free radicals in parasite food vacuole

***Coartem is available in US for treatment of uncomplicated falciparum malaria

Question 7

What is used for malaria prevention?

Answer 7

• Mefloquine
• Atovaquone and proguanil
• Doxycycline-Multidrug-risk for vaginal candidiasis in women

Primaquine for vivax and ovale for patients without severe G6pD deficiency

Chloroquine-only for areas without resistant falciparum

Question 8

HOw long after can you stop mefloquine, doxy, and chloro vs malarone (atovaquone/proguanil)

Answer 8

you can stop malarone 7 days after instead of 4 weeks because it is causal prophylaxis

Question 9

chloroquine sensitive vivax and ovale infection

Answer 9

chloroquine plus primaquine

Question 10

Uncomplicated Chloroquine resistant P. falciparum

Answer 10

1. Atovaquone-proguanil
2. Artemether-lumefantrine
3. quinine + doxycycline, tetracycline, or clindamycin
4. mefloquine

Question 11

Complicated resistant P falciparum infections

Answer 11

1. quinidine iv + doxy or clinda
2. Artemisinin IV, IM or rectal
3. exchange transfusions if parasite is >10%

Complicated is: coma or severely altered metal status, hypoglycemia, renal failure, parasitemia> 5%, seizures other than 1 short febrile seizure, respiratory distress shock

Question 12

Metronidazole

Answer 12

• *DOC extraliminal (tissue amebiasis)
• also treats giardia, trichomonas

**used for tissue stages of amebiasis including dysentery ameboma, and liver abscess

MOA: ferredoxin linked process reduce nitro group to product that is lethal against anaerobic organisms

ADR: metallic taste, nausea, vomiting, disulfiram like

Drug interactions: anticoags, alcohol, anticonvulsants

Question 13

Giardia

Answer 13

Primary: metronidazole, nitazoxanide

Alternate agents: furazolidone, albendazole

Question 14

Giardia

Answer 14

Primary: metronidazole, nitazoxanide

Alternate agents: furazolidone, albendazole

Question 15

Cryptosporidiosis

Answer 15

• lactose free diet
• antimotility agent
• restoration of immune response HIV**
• Nitazoxanide-immunocompetent and moderately immunosuppressed HIV **
• paromomycin

-other potentially active: azithro and clarithro

Question 16

Leishmaniasis

Answer 16

1. Sodium Stibogluconate
Mainstay treatment
ADRS: gi, fever, HA, myalgias, arthralgias, rash, QT prolongation 
-only available through CDC 
2. Amphotericin B
3. Liposomal amphotericin B
4. Miltefosine

Question 17

Trypanosomiasis African

T brucei gambiense or rhodesiense

Answer 17

1. Suramin
   - first line for hemolymphatic disease**
   - doesnt cross BBB
2. Pentamidine -alt to suramin
   - doesnt cross BBB
3. melarsoprol
   - only available agent for late stage rhodesiense infection

Question 18

American

T cruzi

Answer 18

Nifurtimox
-DOC
-decreases severity/eliminates detectable parasite
-does not eradicate infection/ not effective for chronic disease management
-efficacy variable/resistance noted
ADR: GI, rash, CNS
benznidazole

Question 19

Neruocysticercosis

Answer 19

Intraventricular-surgery and corticosteroid+- antihelminitics

Albendazole and Praziquantel

Question 20

Albenzaole

Answer 20

-pinworm, ascariasis, hookworm, trichuriasis, strongyloidiasis, echinococcosis, neurocysticercosis

ADR:
long term: elevated aminotransferases, GI effects
- 2 days after treatment my see inflammation and increased ICP with neurocysticercosis

Question 21

Praziquantel

Answer 21

schistosomiasis, clonorchiasis, paragonimiasis, neurocysticercosis

decreased bioavailability with corticosteroid therapy

ADRs: HA, drowsiness, dizziness abdominal pain

Contraindications: ocular cysticercosis (inflammation)

Cautions: pregnancy and lactation

Question 22

Mebendazole

Answer 22

Ascariasis, hookworm, pinworm. taeniasis, trichinosis, strongyloidiasis

ADRs: minimal Gi to neutropenia and hepatic with long term therapy; hypersensitivity

avoid during first trimester and children under two

Drug interactions: carbamazepine and dilantin

Question 23

Pyrantel Pamoate

Answer 23

Pinworm; ascaris
-not trichuriasis or strongyloidiasis
Luminal agent
MOA: depolarizing neuromuscular block-cuases release of AcH and inhibition of cholinesterase resulting in worm paralysis

Caution: Liver disease; kids

Question 24

Filariases

Answer 24

Diethylcarbamazine

Question 25

Onchocerciasis

Answer 25

Ivermectin

Question 26

Ivermectin

Answer 26

TOC strongyloidiasis and onchocerciasis

• alternative for scabies in aids patients
• bancroftian filariasis, cutaneous larva migrans

MOA: paralyzes nematodes and arthropods by intensify GABA mediated signals

ADR: hypersensitivity from worm death
Mazotti reaction-sever onchocerciasis-fever, headache, dizziness

Cation: preg, existing CNS inflammation

Question 27

quinine and quidine

Answer 27

***DOC for treatment of severe disease with chloroquine resistant falciparum
-used with second agent (doxy) to shorten duration and limit toxicity
ADR:cinchonism
Quinine-used if needed in pregnancy