Anti-parasitic agents Flashcards
Chloroquine
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
Mefloquine
(derivative of chloroquine)
SIDE EFFECT
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
Atovaquone (combination with proguanil)
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
Doxycycline
a semisynthetic tetracycline
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!
Primaquine
***used to treat exoerythrocytic forms of vivax and ovale
MOA: similar to chloroquine Stage: Hypnozoite Gametocyte
Contraindications: granulocytopenia
Relative Contraindications:
**G6PD deficiency
Artemisinin
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
What is used for malaria prevention?
- 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
HOw long after can you stop mefloquine, doxy, and chloro vs malarone (atovaquone/proguanil)
you can stop malarone 7 days after instead of 4 weeks because it is causal prophylaxis
chloroquine sensitive vivax and ovale infection
chloroquine plus primaquine
Uncomplicated Chloroquine resistant P. falciparum
- Atovaquone-proguanil
- Artemether-lumefantrine
- quinine + doxycycline, tetracycline, or clindamycin
- mefloquine
Complicated resistant P falciparum infections
- quinidine iv + doxy or clinda
- Artemisinin IV, IM or rectal
- 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
Metronidazole
- *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
Giardia
Primary: metronidazole, nitazoxanide
Alternate agents: furazolidone, albendazole
Giardia
Primary: metronidazole, nitazoxanide
Alternate agents: furazolidone, albendazole
Cryptosporidiosis
- lactose free diet
- antimotility agent
- restoration of immune response HIV**
- Nitazoxanide-immunocompetent and moderately immunosuppressed HIV **
- paromomycin
-other potentially active: azithro and clarithro
Leishmaniasis
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
Trypanosomiasis African
T brucei gambiense or rhodesiense
- Suramin
- first line for hemolymphatic disease**
- doesnt cross BBB - Pentamidine -alt to suramin
- doesnt cross BBB - melarsoprol
- only available agent for late stage rhodesiense infection
American
T cruzi
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
Neruocysticercosis
Intraventricular-surgery and corticosteroid+- antihelminitics
Albendazole and Praziquantel
Albenzaole
-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
Praziquantel
schistosomiasis, clonorchiasis, paragonimiasis, neurocysticercosis
decreased bioavailability with corticosteroid therapy
ADRs: HA, drowsiness, dizziness abdominal pain
Contraindications: ocular cysticercosis (inflammation)
Cautions: pregnancy and lactation
Mebendazole
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
Pyrantel Pamoate
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
Filariases
Diethylcarbamazine
Onchocerciasis
Ivermectin
Ivermectin
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
quinine and quidine
***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
