7 Anti-Protozoal Drugs Flashcards
mixed amebicide
metronidazole
what are the 3 types of amebicides?
- Mixed
- luminal
- systemic
luminal amoebicide
diloxanide furoate
systemic amebicide
choloroquine
MOA of metroniazole
metronidazole= electron acceptor
amoebas have ferrodoxin like compounds which activate metronidazole which binds to DNA and causes cell death
you use metronidazole in combination with…
diloxanide furoate
if you take metronidazole you may develop
- metallic taste
- oral fungus
- disulfiram like effects if taken with alcohol
- ->blocks aldehyde dehydrogenase–> aldehyde accumulation–> sickness
if you see prolonged symptoms of metronidazole (metallic taste) you might ask the pt…
have you been taking OTC cimetidine (for heartburn)?
–> its a p450 - and prolongs the plasma half life of metronidazole
you use metronidazole vs…
Giardia lamblia
Entamoeba histolytica
Trichomonas vaginalis
Bacteroides
Clostridium–> C. difficile
on the
Metro
Garderella
luminal amebicide
diloxanide furoate
if you patient is an asymptomatic passer of cyst you should give them
diloxanide furoate
which amebicide is only used for interstinal amebiasis
diloxanide furoate
what drugs can you use for systemic amebicide
- metronidazole
- diloxanide furoate
- chloroquine
you give as a combination
what are the systemic amebicides and what do they prevent
combination of metronidazole, diloxanide furoate, and chloroquine
they prevent amebic liver abscesses–> think abscess=pus
Schizonticides are used vs.
malaria
what 2 organisms cause malaria:
- plasmodium falciparium= deadly
2. plasmodium vivax= milder
if you need to target tissue schizont in a patient with malaria you would use
primaquine
*which you will often use in conjugation with a blood schizonticide, due to its lack of activity against the erythrocytic schizonts
what form of malaria does primaquine eradicate?
Exo-erythrocytic form= the developmental stage in the liver before RBC become infected
primary forms= P. falciparum and vivax
secondary forms=P. vivax and ovale
if the pt had low levels of glucose-6-phosphate dehydrogenase (G6PD deficiency) primaquine can induce
hemolytic anemia
primaquine has…
a low incidence of GI side effects
what are the blood schizonticides?
- chloro-quine
- quinine
- meflo-quine
what are the 4 MOA for cholorquine= blood schizonticide
- enters RBC and interfers with heme polymerase, which the parasites need to survive in RBC
- take up by food vacuoles
chloroquine is basic and when placed in the acidic environment will take up a proton and become trapped, resulting in alkalinization of organelles–> parasite cant carry out hemoglonin digestion - disrupt tertiary structure of nuclei acids–> decreased DNA synthesis
- bind to ferri-proto-porphyrin 9= complex that damages membranes and causes lysis of both parasite and RBC
chloroquine (blood schizonticide)= DOC for
erythrocyte P. falciparum malaria–> except resistant chains
side effects of cholorquine
- electrocardiographic changes
- if used chronically
- -> discoloration of nail beds and visual disturbances
when would you use quinine (blood schizonticide)
for resistant malarial strains
NEVER 1ST CHOICE DRUG FOR MALARIA–> CAN CROSS PLACENTA
what are the effects of overdosing on quinine=cinchonism
- nausea and vomiting
- tinnitus=ringing of the ears
- vertigo
THIS IS REVERSIBLE
what test is used for hemolytic anemia
Coombs test
MOA of mefloquine
damage parasite membrane
characteristic of mefloquine= blood schizonticide
long half life
BIG side effect of mefloquinine= blood schizonticide
CNS ISSUES–> neurotic and psychotic manifestation
-can cause schizophrenia (ppl that come back from iraq and end up killing whole family)
DONT GIVE TO SCUBA DIVERS–> confusion underwater–>death
prophylaxis for malaria
if sensitive–> use cholorquine
if resistant–> use doxycycline (photosensitive so use sunscreen0
what are the 2 organisms for trypanosomiasis
- Trypanosoma brucei–> African sleeping sickness
- Trypanosoma cruzi–> Merican= Chagas’ disease
- -> invades CNS
what are the trypanosomiasis drugs
- melarsoprol
- petamidine isethionate
- nifurtimox
melarsoprol is the DOC used only for…
late stages in african sleeping sickness with CNS involvement for
T. brucei gambiense
T. brucei rhodesiense
melarsoprol (for African sleeping sickness= T. brucei) can cause
encephalopathy which is sometimes reversible but most times not reversible
MOA for pentamidine isethionate= vs trepanosoma
binds to parasite DNA and interferes with synthesis of
- RNA
- DNA
- phospholipids
- protein of parasite
when do you use pentamidine isethionate?
for treatment vs .
1. T brucei gambiense
DURING HEMATOLOGICAL STATE
2. Pneumocystis carinii–> seen in HIV pt
-not effective vs. T cruzi
why would you not give pentamidine isethionate via IV
if you give it IV youll see
- tachcardia
- sharp fall in BP
Pentamidine isethionate is toxic to…
beta cells of the pancreas–> can cause type 1 DM
what is the only drug used for acute T. cruzi infections
nifurtimox (suppressive not curative drug)
MOA of nitrofurtimox (for T. cruzi)
nitroaromatic compound that get reduced– free electron that attacks molecular O2 and forms:
- superoxide
- hydroxy radical
- H2O2
**requires that the organism lacks catalase
what side effects do you see with nifurtimox= for T. cruzi
anaphylaxis and delayed hypersensitivity rxns
drug used for leishmaniasis
sodium stibo-gluconate
MOA of sodium stibo-gluconate= vs leishmaniasis
inhibits phosphofructokinase (PFK)–> which inhibits glycolysis
side effect of sodium stibogluconate= leishmaniasis
cardiac arrhythmias
DOC for Toxoplasma gondii= cat poop (cats= only animal that can shed oocyst in poop)
pyri-methamine
MOA of pyrimethamine= DOC for T. gondii
inhibits dihydrofolate reductase–> reduced tetra-hydrofolate
–> leads to no purines or pyrimidines
MOA= same as TMP
what might you see if you use pyrimethamine vs. T gondii
severe hypersensitivity rxns
possible megaloblastic anemia
most commonly diagnosed intestinal parasite in the US
Giardia lamblia
