Antiprotozoals Flashcards
What is the DOC for symptomatic E. histolytica infx?
metronidazole + luminal amebicide
What is the DOC for giardia lamblia?
metronidazole
what is the dOC for trichomonas vaginalis?
metronidazole
What is the DOC for toxoplasma gondii
pyrimethamine + sulfadiazine + folinic acid (leucovorin)
what is the DOC for pneumocystitis jirovecii
TMP-SMZ + folinic acid (leucovorin)
What are the major adverse reactions to metronidazole?
Dysguesia (metallic taste)
Disulfiram-like reaction
CNS/PNS sxs
For patients with E. histolytica, G. lamblia and T. vaginalis infections who cannot tolerate metronidazole, what is the drug of second choice?
Tinidazole
What is unique regarding the course of treatment with tinidazole vs. metronidazole?
Tinidazole has longer half-life and can be taken once daily
Emetine and Dehydroemetine are only used under what conditions?
severe intestinal/systemic emebiasis infections where metronidazole is ineffective
What limits the use of emetine/dehydroemetine?
cardiotoxicity, serious GI effects, teratogenicity.
only available under compassional use by CDC
What are the DOC for asymptomatic e. hystolytica infections?
paramomycin or iodoquinol
What toxicities accompany iodoquinol?
high iodine content can cause thyroid enlargement
nail/hair/skin/sweat discoloration
rare optic neuritis/atrophy
paromomycin is what kind of antibiotic?
aminoglycoside
why doesn’t paromomycin have oto/nephro toxicity?
because it is not absorbed from the GI tract
when do you consider administration of iodoquinol or paromomycin?
for luminal trophozoites
what is the main side effect for paromomycin?
GI upset or superinfection
What common antibiotics are used as alternative drugs to treat amebiasis and giardiasis in combo with metronidazole?
tetracycline and erythromycin
What is the DOC for toxoplasma gondii?
pyrimethamine/sulfadiazine + Leucovorin
describe the dosage of pyrimethamine + sulfadiazine in the tx of toxoplasmosis
high dose, approaching the toxic level
what is the DOC for pneumocystitis pneumonia from p. jirovecii infection?
TMP-SMZ
What is often given as prophylaxis against p. jirovecii in AIDS patients?
TMP-SMZ
what is pentamidine effective against?
p. jirovecii
what is the mechanism of action for pentamidine?
inhibit DNA replication
what are the toxic side effects of pentamidine?
hypotension, arrhythmia, hypoglycemia
When should you consider using pentamidine for p. jirovecii?
when TMP-SMZ isn’t able to be tolerated
what is another drug that can be considered for patients with p. jirovecii that cannot tolerate TMP-SMZ or don’t want to use pentamidine?
atavaquone + proguanil
What drugs can be used to treat roundworms?
Albendazole, mebendazole, pyrantel pamoate or ivermectin
What are the DOCs for roundworm infection?
Albendasole, mebendazole, or pyrantel pamoate
alebendazole/mebedazole achieve success through what mechanism of action?
inhibit microtubule polymerzation and microtubule-dependent glucose uptake
What is the mechanism of actio for pyrantel pamoate?
cholinesterase inhibitor, produces depolarizing neuromuscular blockade
Ivermectin is effective against what parasites?
roundworms, insects and acarine parasites
what is the mechanism of action for ivermectin?
paralytic, intensifies GABA mediated transmission of signals in peripheral nerves
What is the DOC for tapeworms (cestodes) and flukes (trematodes)?
praziquantel
What is the mechanism for action for praziquantel against tapeworms and flukes?
increases permeability to Ca.
