Antiprotazoal Flashcards
Etiology of amebiasis
E. histolytica
Etiology of giardiasis
Giardia lamblia
Etiology of Trichomoniasis
Trichomonas vaginalis
Etiology of Toxoplasmosis
Toxoplasma gondii
Etiology of PCP
Pneumocystis jirovecii
Symptomatic form of amebiasis
tissue form
Transmission of amebiasis
contaminated food, water or direct contact
Infective form of amebiasis
cysts (trophozoites invade and replicate in tissue)
What do trophozoites invade?
Intestine (diarrhea) and liver (abscess)
Giardiasis transmission
contaminated food, water, direct contact (very low infective dose)
Most common cause of non-bacterial diarrhea
Giardiasis
“beaver fever”
giardiasis
Sexually transmitted
Trichomoniasis
Sx of trich
vaginitis and frothy, yellow discharge
Transmission of toxoplasmosis
animals (especially cats)
Fetal infection of toxoplasmosis
heart problems, hydrocephalus, retinochoroiditis
PCP etiology
pneumocystis jirovecii (carinii); not a protozoa - yeast like fungus
Major cause of death in AIDS patients
PCP (give prophylaxis)
Tissue amebicides
metronidazole, tinidazole, emetine and dehydroemetine
Luminal amebicides
Iodoquinol, Paromomycin, tetracycline & erythromycin
DOC for e. hystolytica
Metronidazole + luminal
Giardia lamblia DOC
metronidazole
Trich vaginalis DOC
metonidazole
Toxoplasma gondii DOC
Pyrimethamine-Sulfadiazine (daraprim)
PCP DOC
Trimethoprim sulfamethoxazole (Bactrim)
Asymptomatic amebiasis tx
luminal (iodoniquinle, paramomycin, tetracycline, erythromycin)
MOA of metronidazole
prodrug that reacts with ferredoxin (anaerobes); metabolites are taken up into DNA and form unstable molecules
Kinetics of metronidazole
O, P, T liver metabolism distributes widely, CSF kills amoeba in tissue; combine w/ luminal eliminated in urine
Side effects of metronidazole
metallic taste (disguesia) disulfiram-like reaction GI distrubance CNS/PNS sx: seizures, peripheral neuropathy (prolonged use) Candida super infection hypersensitivity
Tinidazole use
used for amebiasis, giardia and trich when metronidazole isn’t tolerated
Kinetics of tinidazole
oral; 12 hours half life so one dose/day
Emetine and dehydroemetine (mebadin) use
3rd alternative for severe intestinal or systemic E. histolytica
Emetine and dehydroemetine kinetics
SC or IM (pain, tenderness and weakness at injection site)
emetine and dehydroemetin toxicities
cardiotoxicity
serious GI
teratogenicity
Contra for emetine
renal or cardiac disease
pregnancy
Iodoquinol use
asymptomatic amebiasis
Iodoquinol kinetics
oral; little absorption (luminal)
Toxicities of iodoquinol
skin rxn, H/A, diarrhea
High iodine content- thyroid enlargement
Eye effects (neuritis, atroph) leading to blindness
Paromomycin MOA
aminoglycoside; 30s subunit
Paromomycin kinetics
Oral, cream (t. vaginalis)
not signnificantly absorbed from GI (luminal)
Paromomycin use
asymptomatic amebiasis (w/ metro of symptomatic), giardiasis, T. vaginalis
Side effect of paromomycin
GI upset
Tetracycline and erythromycin use
amebiasis and giardiasis (+ metro for symptomatic)
DOC for toxoplasmosis
Daraprim
Toxicity of daraprim
heme disorder at high dose
What do you give with daraprim and why?
Leucovorin; folic acid syn inhibitor (DHFR)
PCP DOC
Bactrim
MOA of Bactrim
folic acid syn inhibitor
Use of Bactrim
DOC for PCP
Can be used as 2nd option for toxoplasmosis (daraprim is firrst)
Prophylaxis for P. jirovecii in HIV
Bactrim (30% of patients can’t tolerate; give pentamidine instead)
Pentamidine use
alternative for PCP (P. jirovecii) in those that can’t tolerate bactrim
MOA of pentamidine
inhibit DNA replication
Pentamidine kinetics
IM injection (active) or nebulization (prophylaxis)
Toxicities of pentamidine
hypoglycemia, hypotension, arrythmias (occasion: hyperglycemia, tachy, H/A, vomiting, bronchospasm, renal dysfunction, Ca loss, hepatic failure)
Nematodes
Roundworms
Cestodes
Tapeworms
Trematodes
flukes
Shistosomes
blood flukes
MOA of antihelminthic tx
energy metabolism
neuromuscular coordination
microtubular function
cell permeability
DOC for roundworms
abendazole, mebendazole or pyrantel pamoate
Alternative for round worm tx
ivermectin
DOC for flukes
praziquantel
DOC for tapeworms
Praziquantel
Alternate for flukes
bithionol
Alternate for tapeworms
Niclosamide
Albendazole/Mebendazole kinetics
Oral
broad-spectrum: round, whip, hook, pin (mixed roundworm infections)
MOA of albendazole/mebendazole
inhibits microtubule polymerization by binding to B-tubulin; inhibits microtubule-dependent uptake of glucose leading to immobilization and death
Effects of albendazole/mebendazole
embryotoxic/teratogenic
well tolerated- some ab discomfort
Monitor LFT in long term tx
Pyrantel pamoate kinetics
Oral;
broad spectrum (round, pin, hook)
Available OTC
MOA of pamoate
cholinesterase inhibitor; produces depolarizing neuromuscular blockade in the worm
OTC tx for roundworm
pyrantel pamoate
Ivermectin use
alternative for roundoworm tx; (nematodes, insects, and acarine parasites, threadworm , round, cutaneous larva migrans)
MOA of ivermectin
paralyzes parasite; intensifies GABA-mediated transmission of signals in peripheral nerves
Side effects of ivermectin
minimal, pruritus, tender lymph nodes and fever
Praziquantel use
DOC for flukes and tapeworm (all schistosomes too)
Praziquantel kinetics
oral
MOA of praziquantel
increasing worms permeability to Ca, results in contraction and paralysis of worms muscles, dislodgement and death
Side effects of praziwuantel
N/V, ab discomfort
Bithionol use
alternative for fluke tx
Only DOC for sheep liver flukes
Side effects of bithionol
mild N/V, H/A, diarrhea, dizziness, urticaria, and rash
What are the toxic effects of antihelmnith tx due to
release of antigens from dying worm