Antoprotozoals And Antihelmintic Agents Flashcards
What is the etiology of amebiasis?
Entamoeba histolytica
What are the two forms of E. Histolytica and which one is the infective one?
Cysts = infective
Trophozoites
What are the two phases of E histolytica, and which one is symptomatic?
Liver phase=symptomatic
Lumen phase =asymptomatic
If one person in the household has e. Histolytica, do you need to treat the rest of the household?
Yes, it is spread via food, water, and contact, and is a “population” disease. Usually the whole household is infected
What is the etiology of giardiasis?
Giardia lamblia
How is trichomoniasis spread?
Sexually
If one person has trichomoniasis, does their partner?
Yes you need to treat both partners. Men are usually asymptomatic though.
What is the characteristic symptom of trichomoniasis in women?
Vaginitis
Frothy yellow discharge 🤮
Is toxoplasmosis a big deal for healthy people?
No, it is a mild infection in people with good immune systems
Is toxoplasmosis a big deal for pregnant women and immunocompromised peopel
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Yes, can cause major problems to the fetus and can be life threatening to someone with an incompetent immune system
What is the etiology of pneumocystis aka PCP?
Pneumocystis jirovecii
Pneumocystis carinii
For what population is pneumocystosis a big deal?
AIDS patients
MAJOR cause of death for them via pneumocystis pneumonia
What drugs are the tissue amebicides for entamoeba histolytica?
Metronidazole
Tinidazole
Emetine + Dehydroemetine
What are the luminal amebicides used for asymptomatic luminal phases of entamoeba histolytica?
Iodoquinol
Paromomycin
Tetracycline and erythromycin
What is the drug of choice for entamoeba histolytica?
Metronidazole (with or without a luminal amebicide)
You would give just the luminal amebicide if they were asymptomatic- no metronidazole
What is the DOC for giardia?
Metronidazole
What is the DOC for trichomonas vaginalis?
Metronidazole
What are the DOCs for toxoplasma gondii (toxoplasmosis)?
Pyrimethamine-sulfadiazine + leucovorin
What are the DOCs for pneumocystis jirovecii/carinii?
Bactrim + leucovorin
How many treatments of metronidazole do we give for giardiasis or trichomoniasis?
Single treatment
How does metronidazole get activated?
It gets reduced by ferredoxin, which is only in anaerobes
What is the MOA of metronidazole?
Its metabolites are taken up into DNA where they form unstable molecules
Will metronidazole kill amoebas in luminal phase?
No, must combine with luminal agent
What are the side effects of metronidazole?
Metallic taste
Disulfiram-like reaction
Nervous system toxicity with prolonged use, but we don’t use metronidazole for long periods
GI upset, superinfection
What is the main point about tinidazole?
It’s a metronidazole alternative
When would we use emetine + dehydroemetine (Mebadin)?
Severe amebiasis infections in which metronidazole didn’t work
(Last resort, very toxic)
What are the side effects of emetine+dehydroemetine (mebadin)?
Cardiotoxicity**
Serious GI upset
Teratogenicity**
If someone is pregnant and metronidaozle didn’t work for their amebiasis infection, can we give them an injection of emetine+dehydroemetine(Mebadin)?
NO VERY TERATOGENIC
Who can NOT have emetine+dehydroemetine (Mebadin)
Heart disease
Kidney disease
Pregnant women
What is the main use of iodoquinol?
Luminal phase of e. histolytica aka asymptomatic amebiasis
What are the toxicities of iodoquinol?
Iodine-induced thyroid enlargement
Eye problems, possible blindness
What do we use paromomycin for?
Asymptomatic amebiasis
Giardiasis
Trichomonas vaginalis
What are the side effects of paromomycin?
GI upset!
Even though it is an aminoglycoside, you don’t get ototoxicity/nephrotoxicity since it is not significantly absorbed
What kind of medication is paromomycin?
Aminoglycoside
What are tetracycline and erythromycin used for?
Alternative treatments for amebiasis and giardiasis after paromomycin didn’t work either
What other drug will be given with tetracycline/erythromycin for symptomatic amebiasis patients?
Metronidazole
What is the drug of choice for toxoplasmosis?
Pyrimethamine + sulfadiazine
What kind of infection is toxoplasmosis (toxoplasma gondii)?
Opportunisitic infection
Is pyrimethamine + sulfadiazine static or cidal?
It is static,
So, it can be given prophylactically for toxoplasmosis, as well as can be given for active infection, but will not clear the infection.
What should you give with pyrimethamine+sulfadiazine?
Leucovorin**
What is the drug of choice for pneumocystis pneumonia (caused by P. jirovecii/P. carinii)?
Bactrim
Don’t forget it is a sulfa
30% of AIDS patients can not tolerate Bactrim :(
And since pneumocystis pneumonia is one of the biggest killers of AIDS patients, what are they supposed to take?
Pentamidine
What is pentamidine usually reserved for?
Patients who can’t tolerate bactrim
Not as effective and more toxic though
What microbe causes pneumocystis pneumonia (PCP)?
Pneumocystis jirovecii
Or pneumocystis carinii
(It is a yeast like fungus)
What is the mechanism of action of bactrim? I forgot
Inhibition of folate metabolism
Synergy between trimethoprim and sulfamethoxazole
What are the main toxicities of bactrim? I forgot
Hypersensitivity
Stevens Johnson syndrome
Photosensitivity
Aplastic anemia for G6PD
When you treat someone with an antihelminthic drug, what usually causes the side effects?
The worms dying. Not the drug
It’s usually just some flu-like symptoms
What are the DOCs for roundworms (nematodes)?
Albendazole
Mebendazole
Pyrantel pamoate
What is the MOA of albendozole and mebendazole?
Binds to B-tubulin and inhibitis the microtubule-dependent uptake of glucose
(Starves the worms)
What is an alternative treatment for roundworms(nematodes)?
Ivermectin
DOCs were albendazole, mebendazole, or pyrantel pamoate
What are the adverse effects of albendazole and mebendazole?
Kills fetuses
Do not use in pregnant women
What is the MOA of pyrantel pamoate?
Its a cholinesterase inhibitor that produces a depolarize game neuromuscular blockade
What is the MOA of ivermectin?
Paralyzes the worm by intensifying GABA-mediated transmission of signals in peripheral nerves
What is the DOC for flukes and tapeworms?
Praziquantel
What is an alternative treatment for flukes?
Bithionol
DOC is praziquantel
What is an alternative treatment for tapeworms?
Niclosamide
DOC is praziquantel
What is the MOA of praziquantel?
Increasing worm’s permeability to Ca++, resulting in contraction and paralysis of the worms muscles
(Dislodges the worm)
What is the MOA of bithionol?
Uncoupled oxidative phosphorylation= no ATP synthesis
Paromomycin is an aminoglycoside, so will we see the same ototoxicity and nephrotoxicity we see with other aminoglycosides?
No, because it is not well absorbed from GI tract
