Anti-Protozooals Flashcards
1
Q
How do we get malaria?
A
- 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).
2
Q
What is chloroquine (CQ)?
A
- 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.
3
Q
What is quinine?
A
- similar to chloroquine (inhibits parasite’s heme detoxification).
- alkaloid derivative from Peruvian bark of Cinchona tree.
4
Q
What can quinine toxicity cause?
A
- cinchonism= tinnitus, headache, and dizziness
- hypoglycemia
- blackwater fever (can come from malaria also)= hemoglobinuria
5
Q
What is mefloquine?
A
- 4-methanolquinoline= highly effective blood schizonticide used for malaria.
- contraindicated in pts on B-blockers.
6
Q
What is a toxicity of mefloquine toxicity?
A
- neuropsyychiatric (dysphoria, somnolence, vivid dreams, encephalopathy, psychosis, depression, seizure).
7
Q
What is atovaquone?
A
- 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
8
Q
What is Proguanil?
A
biguanide that is metabolized via P450. Inhibits plasmodial dihydrofolate reductase.
9
Q
** What is malarone?
A
- combination of Atovaquone + Proguanil.
* not recommended in children, pregnancy or breast feeding women.
10
Q
What other drug can treat plasmodium (malaria)?
A
tetracycline (doxycycline)
11
Q
** What is primaquine?
A
- 8-aminoquionoline= effective against intrahepatic forms of plasmodium (malaria) and RELAPSING malaria (hypnozoite formation). It damages plasmodial mitochondria via oxidative stress.
12
Q
What is a problem with primaquine?
A
- causes hemolytic anemia in patients with G6PD deficiency.
- never give parenterally= marked hypotension.
13
Q
What are artemisinins?
A
- “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
14
Q
What is sulfadoxine-pyrimethamine?
A
- limited use for malaria because of serious ADRs
15
Q
What is pyrimethamine?
A
- blocks synthesis of nucleic acid and folate in plasmodium and T. gondii.
- company raised price of this drug a few years ago causing issues.