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117 Cards in this Set
- Front
- Back
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What are the 4 species of plasmodium that cause malaria?Which is responsible for the majority of serious complications and deaths? Which is responsible for the most resistance?
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1)vivax, malaraie, falciparum and ovale
2) falciparum 3) falciparum |
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What vector transmits plasmodium sporozoites?
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anopheles mosquito
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Once sporozoites of plasmodium are in blood what happens?
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they go to the liver and undergo the exoerythrocytic stage to form mature schizonts in the liver
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What plasmodium form is released from the liver following the exoerythrocytic stage?
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merozoites are released and invade RBCs
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Where are the sexual stage gametocytes formed?
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in the RBCs. This has to occur before they are taken back up into mosquitos
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In a plasmodium falciparum and malaraie infection how many rounds of replication occur? What is the recovery time for the liver?
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1 round and recovery in 4 weeks
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which plasmodium species can form a dormant hypnozoite in the hepatic stage of infection?
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ovale and vivax can cause recurrent infections
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What are drugs called that can eliminate developing and dormant liver forms of plasmodium? what about drugs that act on RBC parasites? Drugs that prevent the sexual stage and prevent transmission?
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tissue schizonticides
blood schizoniticides gametocides |
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Chemoprophylatic agents for plasmodium are effective against what stage?
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they kill the erythrocytic parasites
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What type of agent is chloroquine?
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blood schizonticide
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What is the mechanism of chloroquine?
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concentrates in vacoules of parasites and prevents the breakdown of heme. Free heme accumlates and is toxic
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What is plasmodium species in resistant to chloroquine? What is the mechanism of resistance? What drug can be given with chloroquine to reverse resistance?
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1) falciparum
2) resistance via mutation in a putative transporter PfCRT 3) verapamil, desipramine, chlorpheniramine can help with resistance |
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If metronidazole fails to clear amebic liver abscess what antiprotozoal drug can be given?
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chloroquine
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What is an adverse effect of chloroquine in africans? What are other adverse reactions in general to chloroquine?
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1) pruitus
2) malaise, fatigue, anorexia, nausea, vomiting, BLURRED VISION, urticaria |
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A person is given chloroquine to prevent malaria on vacation. On vacation he develops impaired hearing, confusion, psychosis, seizures, agranulocytosis, dermatitis, alopecia, hair bleaching and hypotension. What does he have?
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He has a GDP6 deficiency and as a result is having a hemolytic reaction with chloroquine
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chloroquine can be given for rheumatologic diseases. What side effects are possibly with longterm treatment?
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irreversible ototoxicity, retinopathy, myopathy and peripheral neuropathy
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What people is chloroquine contraindicated in?
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porphyria or psoriasis, people with hearing or vision problems or myopathy
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What common antidiarrheal drugs can impede the absorption of chloroquine?
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calcium and magnesium antacids
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What is amodiaquine an alternative for? What are its side-effects? When is it given?
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1) chloroquine
2) agranulocytosis, aplastic anemia, and hepatotoxicity 3) when chloroquine resistance is a problem and becuase it has fewer side effects it is usually given with artesunate |
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What is the first line therapy for falciparum?
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quinine and quinidine
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Quinine is highly effective against all forms of plasmodia blood schizonts. What species is it gametocidal for?
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vivax and ovale
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What antimalarial drug should be given while using a cardiac monitor?
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quinidine has cardiac toxicity and should be monitored
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What is first line therapy for babesia microti (babesiosis)?
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quinine with clindamycin
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What is quinine derived from?
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the bark of the cinchona tree
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What drug causes cinchonism? what are the features?
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quinine and quinidine cause headache, tinnitus, nausea, dizziness, flushing and visual disturbances
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What genetic condition should be screened before giving someone quinine?
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G6DP will result in hemolysis
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what effects can quinine have a blood cells?
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cause leukopenia, agranulocytosis, and thrombocytopenia
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Why is quinine contraindicated in diabetics and pregnant woman?
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quinine can stimulate insulin release. Therefore it may cause hypoglycemia in a diabetic. It can also stimulate uterine contractions
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What is blackwater fever and what cuases it?
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It is caused by a hypersensitivity to quinine that results in severe hemolysis with hemoglobinuria.
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Like chloroquine, quinine should be avoided in patients with what sensory deficits?
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Visual or auditory
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What is mefloquine effective against?
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chloroquine resistant falciparum
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mefloquine is active against falciparum and vivax at what stage?
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blood schizont
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As with chlorquine, mefloquine must be taken with primaquine to be effective against what plasmodium species?
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vivax and ovale
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What are side effects of weekly chemoprophaxylaxis with mefloquine?
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nausea, vomiting, dizziness, SLEEP AND BEHAVIORAL disturbances, epigastric pain, diarrhea, headache and rash, SEIZURES AND PSYCHOSIS
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Who is it contraindicated to give mefloquine to?
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should not be given to people with epilepsy, psychiatric disorders, arrythmia and cardiac conduction defects
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What is the drug of choice for people infected with ovale or vivax?
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primaquine because it targets the hypnozoite (the dormant liver form). Note: this can be used as chemoprophyaxis for all plasmodium species
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What drug is gametocidal, tissue and blood schizonticidal?
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primaquine. Note: it is weak against the erythrocyte stage it is best against liver stage infection
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What drug combination can be given to treat pneumocystis jiroveci?
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clindamycin and primaquine
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What are the adverse effects of primaquine?
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nausea, epigastric pain, headache, leuckopenia, agranulocytosis, leukocytosis and cardiac arrythmias, methemoglobinemia
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Who is it contraindicated to give primaquine to?
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people with G6PD deficiency and pregnancy
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What can atovaquone be used to treat aside from plasmodia?
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pneumocystis jiroveci
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How does atovaquone work?
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acts against plasmodia by disrupting the mitochondrial electron transport.
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what stage of plasmodium is atovaquone active against?
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erythrocytic schizonts
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What two drugs are combined to make malarone?
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atovaquone and progaunil
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pyrimethamine is a folate synthesis inhibitor and is related to what drug?
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trimethoprim
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What is fansidar is composed of what two drugs?
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sulfadoxine and pyrimethamine
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What forms of plasmodium are pyrimethamine and proguanil active against?
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act against all 4 species by slowly acting against the erythrocytic stage
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What is the mechanism of action of pyrimethamine and proguanil? What do sulfonamides inhibit?
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inhibits plasmodial dihydrofolate reductase.
dihydropteroate synthase |
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What is the first line therapy against toxoplasmosis?
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pyrimethamine with sulfadiazine
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What kind of organism is pneumocystis jiroveci? What agents are effective against it?
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a fungus that is susceptible to antiprotozoal agents
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What is fansidar is composed of what two drugs?
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sulfadoxine and pyrimethamine
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What forms of plasmodium are pyrimethamine and proguanil active against?
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act against all 4 species by slowly acting against the erythrocytic stage
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What is the mechanism of action of pyrimethamine and proguanil? What do sulfonamides inhibit?
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inhibits plasmodial dihydrofolate reductase.
dihydropteroate synthase |
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What is the first line therapy against toxoplasmosis?
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pyrimethamine with sulfadiazine
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What kind of organism is pneumocystis jiroveci? What agents are effective against it?
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a fungus that is susceptible to antiprotozoal agents. first line therapy is with trimethoprim and sulfamethoxazole
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What toxicities result from folate synthesis inhibitors?
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nausea, vomiting, fever, rash, leukopenia, hyponatremia, elevated hepatic enzymes, azotemia, anemia, and thrombocytopenia, pancreatitis and hypercalcemia
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Fandisar use can result in what adverse effects?
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erythema multiforme, steven-johnson syndrome and toxic epidermal necrolysis
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What is Steven-johnson syndrome?
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it is a hypersensitivity reaction that causes mucocutaneous lesions everywhere
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How do antibiotics against that work against bacterial protein synthesis also work against protozoa?
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They inhibit protein synthesis in a plasmodial prokaryote-like organelle called the apicoplast
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What form of plasmodium are tetracycline and doxycycline active against?
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erythrocytic schizonts
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What is an alternative antibacterial treatment for intestinal amebiasis?
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tetracycline and erythromycin
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What stages of plasmodium infection is halofantrine effective against?
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erythrocytic stage of all 4 species
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What are the major side effects of halofantrine?
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cardiac toxicity, headache, rash, pruitus, elevated liver enzymes
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What are the analogs of artemisinin?
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artesunate, artemether and dihydroartemisin
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What species of plasmodium are susceptible to artemisinins?
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all 4
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What is an alternative antibacterial treatment for intestinal amebiasis?
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tetracycline and erythromycin
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What stages of plasmodium infection is halofantrine effective against?
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erythrocytic stage of all 4 species
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What are the major side effects of halofantrine?
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cardiac toxicity, headache, rash, pruitus, elevated liver enzymes
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What are the analogs of artemisinin?
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artesunate, artemether and dihydroartemisin
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What species of plasmodium are susceptible to artemisinins?
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all 4. it acts as a blood schizonticide
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What causes amebiasis?
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entamoeba hystolytica
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what can entamoba hystolitica cause?
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aymptomatic intestinal infection, mild to moderate colitis, severe intestinal infection (dysentery), ameboma, liver abcess and extraintestinal infections
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What is the standard treatment for asymptomatic intestinal infection?
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luminal amebicides like diloxanide furoate, iodoquinol, paromomycin
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What is treatment of choice for amebic colitis?
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luminal amebicide (diloxanide furoate, iodoquinol, paromomycin) plus metronidazole can use tetracycline or erythromycin
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What is the treatment of choice for extraintestinal infections?
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luminal amebicide plus metronidazole
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What causes amebiasis?
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entamoeba hystolytica
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what can entamoba hystolitica cause?
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aymptomatic intestinal infection, mild to moderate colitis, severe intestinal infection (dysentery), ameboma, liver abcess and extraintestinal infections
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What is the standard treatment for asymptomatic intestinal infection?
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luminal amebicides like diloxanide furoate, iodoquinol, paromomycin
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What is treatment of choice for amebic colitis?
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luminal amebicide (diloxanide furoate, iodoquinol, paromomycin) plus metronidazole can use tetracycline or erythromycin
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What is the treatment of choice for extraintestinal infections?
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luminal amebicide plus metronidazole (1st choice)
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What forms of entameba hystilytica can be treated with metronidazole?
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kills trophozoites but not cysts good for intestinal and extraintestinal infections
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What group do metronidazole and tinidazole belong to? what is the difference between the 2 drugs?
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They belong to the nitroimidazoles. tinidazole has less toxic
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What is the mechanism of action of metronidazole?
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it is chemically reduced in anerobic bacteria and certain protozoa. the reduced products are reactive and cidal
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nitroimidazoles are not effective alone against luminal parasites and must coupled with what?
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luminal amebocides like parmomycin, diloxanide furoate and iodoquinol
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What is the treatment of choice for giardiasis?
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metronidazole
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What is the treatment of choice for trichomoniasis?`
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metronidazole
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What are the adverse effects of metronidazole?
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nausea, headache, dry mouth, METALLIC TASTE are common. Rare are vomiting, weakness, insomnia, thrush, rash, dysuria, dark urine, paresthesias, neutropenia
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Why is it important to instruct pateints not to consume alcohol with metronidazole?
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it has a disulfuram effect that cuases nausea and vomiting
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What drugs do metronidazole potentiate?
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coumarin-type anticoagulants
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What drugs can metronidazole accelerate the elimination of?
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phenytoin and phenobarbital
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Should metronidazole be avoided during pregnancy?
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yes, it may be teratogenic
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Can an organism that is embedded in the intestinal wall be eliminated by iodoquinol?
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no it is not effective against trophozoites in the intestinal wall or extraintestinal tissues
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What are common side effects of iodoquinol?
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anorexia, nausea, vomiting, abdominal pain, rash, pruritus
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With longterm and excessive usage of iodoquinol what can result?
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neurotoxcity
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What class of drug is paromomycin?
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aminoglycoside
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With renal insufficiency what anitamebic should not be given?
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paromomycin
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What does the drug pentamidine work against?
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pneumocystis jiroveci and early infections with trypanosome protozoans, leishmaniasis
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What are the adverse effects of pentamidine?
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highly toxic with rapid delivery causing severe hypotension, tachycardia, dizziness and dyspnea, PANCREATIC TOXICITY resulting in hypoglycemia for days then hyperglycemia
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What is a first line agent against cutaneous and visceral leishmanias?
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sodium stibogluconate
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What adverse reactions occur in someone taking sodium stibgluconate?
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GI symptoms, fever, headache, myalgias, arthralgias and rash, long QT
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What two bugs are treated with nitazoxanide?
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giardia lamblia and cryptosporidum parvum
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What does the active metabolite or the prodrug nitazoxanide inhibit?
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pyruvate: ferredoxin oxidoreductase pathway
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Can nitazoxanide be given to nursing pregnant woman?
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yes it appears to not be mutagenic
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What is suramin effective for? What stage is it effective for?
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trypanosome brucei (east african trypanosomiasis). It is effective against the early stages but can cannot cross into CNS and therefore will not work against later stages
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suramin like all trypanosomiasis treatments lacks efficacy, safety or both. What are the adverse effects?
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immediate reactions include siezures, fatigue, nausea, shock and death. later reactions are renal abnormalities, fever, rash and neuropathies
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What is melasoprol used to treat?
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1st line therapy for advanced east african trypanosomiasis (T. brucei) because it can cross CNS. It is 2nd line in west african
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Is melasoprol toxic?
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extremely. it accumulates in CNS, it causes fever, arthralgias, abdominal pain, encephalopathy like seizures, cerebral edema, coma and death
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What is similar between eflornithine and melarsoprol in the treatment of trypanosome brucei?
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it accumulates in CNS
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What is the mechanism of action of eflornithine?
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inhibits ornithine decarboxylase
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What is the most commonly used drug to treat american trypanosomiasis?
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nifurtimox which is a nitrofuran
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what is american trypanosomiasis?
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chagas disease caused by trypanosma cruzi
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Is nifurtimox better for acute or chronic chagas disease? What are side effects?
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1)acute
2) seizures, restlessness, neuropathies, rash, fever |
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What are alternative drugs for the treatment of leishmanias?
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1) amphotericin
2) miltefosine is a alkylphosphocholine analog used for visceral leishmaniasis 3)parmomycin |
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(RB)
what parasites lack the ability to use exogenous folate? |
sporozoans such as plasmodium, toxoplasma, eimeria
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RB
What type of protozoans use pyruvate: feredoxin reductase? |
anearobic protozoans like trichomonas and entameoba
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RB
What is the product of pyruvate: ferredoxin oxidoreductase? |
acetyl CoA via electron transport
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RB
Under anerobic conditions what occurs when a nitroimidazole is in a protozoa? |
electrons are transfered from pyruvate to metronidazole reducing it and activating it
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