Anti-Protozooals Flashcards
How do we get malaria?
- sporozoites are transmitted through mosquito (vector) saliva into host. They go to the liver and then go on to infect the RBCs.
- remember vectors bite twice (once to get infected, and once to transmit).
What is chloroquine (CQ)?
- 4-aminoquinolone that interferes with the malaria parasite’s (plasmodium) heme detoxification. It kills only the erythrocytic stage of infection.
- asexual malaria parasites flourish in host erythrocytes by digesting Hb in their acidic fluid vacuoles, a process that generates free radicals and heme (toxic to the parasite). However, they sequester heme as an insoluble unreactive malarial pigment called HEMOZOIN.
What is quinine?
- similar to chloroquine (inhibits parasite’s heme detoxification).
- alkaloid derivative from Peruvian bark of Cinchona tree.
What can quinine toxicity cause?
- cinchonism= tinnitus, headache, and dizziness
- hypoglycemia
- blackwater fever (can come from malaria also)= hemoglobinuria
What is mefloquine?
- 4-methanolquinoline= highly effective blood schizonticide used for malaria.
- contraindicated in pts on B-blockers.
What is a toxicity of mefloquine toxicity?
- neuropsyychiatric (dysphoria, somnolence, vivid dreams, encephalopathy, psychosis, depression, seizure).
What is atovaquone?
- hydroxynaphthoquinone= inhibitis pre-erythrocytic development of parasite in liver and interferes with cytochrome electron transport and DNA replication.
- used for malarai (plasmodium), pneumocystis jiroveci, T. gondii, and Bebesia
What is Proguanil?
biguanide that is metabolized via P450. Inhibits plasmodial dihydrofolate reductase.
** What is malarone?
- combination of Atovaquone + Proguanil.
* not recommended in children, pregnancy or breast feeding women.
What other drug can treat plasmodium (malaria)?
tetracycline (doxycycline)
** What is primaquine?
- 8-aminoquionoline= effective against intrahepatic forms of plasmodium (malaria) and RELAPSING malaria (hypnozoite formation). It damages plasmodial mitochondria via oxidative stress.
What is a problem with primaquine?
- causes hemolytic anemia in patients with G6PD deficiency.
- never give parenterally= marked hypotension.
What are artemisinins?
- “sweet wormwood,” potent and rapidly acting blood schizonticide that inhibits calcium adenosine triophosphatase, destroying plasmodium via free radical release (attacks parasite cell membrane).
- used in other countries.
- induces P450
What is sulfadoxine-pyrimethamine?
- limited use for malaria because of serious ADRs
What is pyrimethamine?
- blocks synthesis of nucleic acid and folate in plasmodium and T. gondii.
- company raised price of this drug a few years ago causing issues.
Can quinine induce abortion?
YES :(
Besides plasmodium species, what are the other 2 intra-erythrocytic organisms?
Bebsia (pig borne) and Bartonella
What 2 drugs can we use to treat COMPLICATED malaria?
- Guinidine gluconate (IV) then switch to oral.
2. Artesunate
Is there some immunity in malaria?
may be some but not a lot
What is Dapsone?
- widely used Rx of leprosy, PCP, toxoplasmosis, and leishmaniasis.
- inhibits plasmodial dihydropteroate synthase, folic acid synthesis.
What is dapsone syndrome?
- rash, fever, jaundice, and eosinophilia
What is metronidazole?
- antibiotic used for anaerobic bacteria and protozoa. It forms free radical metabolites that causes DNA damage and death of organism.
What can metronidazole toxicity cause?
- disulfiram-like effect= abdominal distress, vomiting, flushing, and headache with alcohol consumption.
- peripheral neuropathy
- enceophalopathy
What is pentamidine?
inhibits DNA, RNA, protein, and phospholipid synthesis used for trypanosomiasis, pneumocystis jiroveci, and leishmaniasis
For what is miltefosine used?
- leishmaniasis
*** For what is nitazoxanide used?
- cryptosporidiosis and giardiasis
For what is furazolidone used?
- giardiasis
What parasite is paromycin (aminoglycoside) sometimes used?
- Entamoeba histolytica
