Anti-Parasitix Flashcards

1
Q

Metronidazole

A

MOA: inhibits Pyruvate:Ferrodoxin Oxidoreductase I (**unique enzyme target only found in parasite)–>↑toxic radicals–>damage to DNA and ↓nucleic acid synthesis
“GETGAP on the METRO”
Giardia, Entamoeba, Trichomonas, Gardneralla, Anaerobes (e.g. Bacteroides, C. diff), H. pylori all treated by METROnidazole

ADME:

ADE: Metallic taste
Disulfiram reaction
Discolored urine
Teratogen (CI in pregnancy and nursing)
Neurologic toxicity
DDI w/ Lithium and Warfarin-->CYP inhibitor
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2
Q

Atovaquone

A

MOA: inhibition of mitochondrial electron transport–>↓ATP and pyramidine synthesis

ADME: lipophilic; ↓bioavailability and efficacy with ↓GI absorption

ADE: hardly any

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3
Q

Iodoquinol

A

MOA: unknown

ADME: 90% remains in intestine and effective against luminal trophozoites

ADE: Thyroid disease, optic neuropathy, renal
NO neurotoxicity

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4
Q

Paromomycin

A

MOA: inhibits initiation complex of protein synthesis; requires O2 uptake

DOC for Amebiasis, Crypto HIV+, and pregnant Giardia pt (avoid metro in pregnancy)

ADME:

ADE: is an Aminoglycoside–>avoid in renal disease
Diarrhea

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5
Q

Pentamidine

A

MOA: unknown. Possibly inhibits DNA ATP topoisomerase, SAM carboxylae, and folate activity

ADME: delivered IV or inhalation (good for lung infection)

ADE: hypotension (↑histamine release)
hypoglycemia (toxic to pancreatic cells
blood dyscrasias
nephrotoxic (inhibition of renal DHFR)
cardiotoxicity

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6
Q

Melarsoprol

A

MOA: metabolized by melarsen oxide–>inhibits TRYPATHIONE REDUCTASE

ADME:

ADE: “ars”=arsenic
febrile reaction–>reactive encephalopathy, peripheral neuropathy

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7
Q

Eflornithine

A

MOA: irreversibly inhibits ORNITHINE DECARBOXYLASE (enzyme in both human and parasite, but in much higher concentration in parasite)

ADME: renally excreted unchanged

ADE: pancytopenia, diarrhea, alopecia

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8
Q

Stibogluconate

A

MOA: Prodrug (pentavalent form)–>toxic (trivalent form)–>changes/inhibits trypanothione reductase and phagolysosomes–>↑efflux of glutathione and trypanothione from cells

ADME: slow release from tissue, then sequestration in macrophages

ADE: chemical pancreatitis
bone marrow suppression

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9
Q

Chloroquine

A

MOA: unknown; PREVENTS POLYMERIZATION OF HEME–>↑accumulation of heme–>toxic to parasite
***Mech of resistance: ↑pumping of drug out of cell (via P-gp) AND out of food vacuole where the heme accumulates
[Used in areas without resistant P. falciparum. Good tx/prophylaxis of P. vivax and ovale]

ADME: metabolized in liver, slow excretion from extensive tissue stores (present for months to years)

ADE: toxic to skin, hair, blood, eyes. Also, ototoxicity and peripheral neuropathy

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10
Q

Quinine

A

MOA: binds DNA and inhibits DNA separation–>blocks DNA replication and transcription
**NOT effective on prophylaxis

ADME: Higher plasma levels in malaria pts due to ↓ liver fxn (can co-adminsiter with rifampin to INDUCE CYP and increase clearance of Quinine)

ADE: ***Hemolytic anemia in pts with G6PD deficiency (just like w/ Primaquine)
Cinchonism (tinnitus, blurred vision, ↓hearing)
Blackwater fever
GI distress
Cardio-depressive + smooth muscle relaxer
Uterine contraction (CI in pregnancy)

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11
Q

Quinidine Gluconate

A

MOA: D-isomer of Quinine–>same MOA
***also a Class IA Antiarrhythmic

ADME: concentrates in high blood flow areas–>heart, liver, skeletal muscle

ADE: Anticholinergic effects (avoid in AV block)

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12
Q

Mefloquine

A

MOA: unknown
***DOC for chloroquine resistance prophylaxis (i.e. even good against P. falciparum)

ADME: concentrates in RBCs where it is highly protein bound

ADE: GI distress, vertigo, visual disturbances, nightmares
CI in B blockers, hx of seizures, other -quines, and pregnancy

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13
Q

Lumefantrine

A

MOA: unknown, similar to mefloquine, coformulated with Artemether (effective against falciparum)

ADME: ↑absorption w/ fatty foods
CYP3A4 interaction

ADE: ↑QT interval

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14
Q

Artemisinins

A

MOA: reacts with ↑Fe in plasmodia in heme–>↑carbon radicals–>alkylate plasmodial molecules
(coadministration w/ lumefantrine effective against falciparum)

ADME: CYP inducer–>↑its own metabolism

ADE: ??…brain, liver, marrow, fetus (avoid in pregnancy and kids)

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15
Q

Primaquine

A

MOA: unknown. Destroys late hepatic stage and latent tissue stage of Vivax/Ovale AND gametocytes of P. falciparum–>can cure relapsing malaria

ADME:

ADE: ***Hemolytic anemia w/ G6PD deficiency (just like Quinine)
GI distress
Methemoglobinemia

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16
Q

Pyramethamine

A

MOA: Similar to trimethoprim, a DHFR inhibitor…often combined w/ sulfadoxine, which inhibits dihyrdropteroate synthase/folate synthesis (effective for falciparum but no Vivax)

ADME: concentrates in RBC. Crosses placenta and breast milk

ADE: Rash (when used w/ sulfas), MEGALOBLASTIC ANEMIA, ↓hematopoiesis

17
Q

-bendazoles

A

MOA: ↓tubulin dimers into polymers–>↓microtubule formation–>↓larvae development
*DOC for GI nematodes

ADME:

ADE: teratogen

18
Q

Ivermectin

A

MOA: ↑Cl- permeability in parasite membrane–>↓glutamate chloride channels and ↓GABA chloride channels–>hyperpolarization–>paralysis
*DOC for Strongyloides and Onchocerca

ADME: lont t1/2

ADE: pruritis and dizziness

19
Q

Diethylcarbamazine

A

MOA: alter/immobilizes fliaria–>increased phagocytosis and possibly organelle damage–>apoptosis
*DOC for Wuchereria bancrofti, Loa Loa, Brugia

ADME:

ADE: host rxn to dying bugs

20
Q

Praziquantel

A

MOA: ↑membrane permeability to Ca+–>↑contraction–>SPASTIC PARALYSIS
***DOC for Schistosome (liver/lung/intestinal flukes) and tapeworms

ADME: lower dose with pts with liver dz

ADE: CI in OCULAR schistosomiasis

21
Q

Pyrantel Pamoate

A

MOA: binds nicotinic receptors–>depolarizing neuromuscular blockade–>spastic paralysis of worm muscle

ADME:

ADE: very few. Try to avoid in pregnancy and kids