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80 Cards in this Set

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Selectivity of Anti-parasitic drugs
1. Unique enzymes to parasite
2. Enzymes indispensable to parasite
3. Common biochemical fxns w/differing pharmacological properties
Diseases caused by luminal and intestinal protozoa
(Hang on to the categories, it's going to get messy)
Amebiasis
Cryptosporidiosis
Cyclosporiasis
Giardiasis
Isosporiasis
Microsporiadiasis
Trichonomoniasis
Cause and Transmission of Amebiasis
E. histolytica
Sexually or fecal oral
3 Stages of Amebiasis
1. Cysts in the lg.--> intestine cause little harm
2. Entamoeba invade the mucosa-> mild to severe colitis (dysentery)
3. Entamoeba invade extraintestinal tissue-> abscess and systemic dz
Treatment of Amebiasis
Luminal drugs
Mixed amebicides
Name the luminal drugs
Diloxanide furoate
Iodoquinol
Paramomycin
Where are the luminal drugs active
Only against the intestinal amoebae
Name a mixed ameibide
Metronidazol
How are the luminal drugs used?
Used to treat asymptomatic or mild intestinal drugs
What do the mixed amebicides treat
Active agains both forms
Use mixed amebicides with?
Diloxanide furonate or iodoquinol
This water born coccidian protaozoan causes diarrhea
Cryptosporidium
Course of illness of Cryptosporidiosis
In immunocompetent- self limiting

In immunocomprimised- chronic diarrhea
CDC recommendation to AIDS patients about water
Only drink boiled, filtered or distilled water to prevent infection
Treatment for Cryptosporidiosis
Paromomycin
Cause of Cyclosporiasis
Cyclospora cayetanensis
Disease caused by Cyclospora
May cause diarrhea in AIDS patients
Treamtent for Cyclospora
Trimethoprim-sulfamethoxazole (TMP/SMZ)
Giardiasis caused by...
Giardia lamblia
Giardiasis causes what?
Traveler's diarrhea from contaminated food or water
Besides eating it how else can you get Giardia?
Person to person transmission (day care centers, etc) oral sexual activity, or go swimming in the streams of Adirondacks N.Y.
Symptoms of Giardia?
Diarrhea, flatulence (ew), nausea, and weakness
Treatment of Giardia
Metronidazole 85-95% effective

Furazolidone
Paromomycin
Which drug for Giardia is not FDA approved?
Metronidazole
Which drug for Giardia is effective in peds patients?
Furazolidone, in a liquid suspension
Which drug for Giardia can be used in pregnant women?
Paromomycin
This coccidian parasite is found in tropical and subtropical locations and causes diarrhea
What is Isospora belli
Treatment for Isosporiasis
TMP/SMZ or pyrimethamine
How many different types of Microsporidiasis are there?
5
Symptoms of microspora infection
Diarrhea
Abdominal pain
Wt. loss
Others: hepatitis, sinusitis, myositis
Treatment for microspora infection
Atovaquone (antibiotic) reduces number of parisites

Albendazole (antihelminth)
Common pathogen of the urogenital tract.
(it's not E. coli)
Trichomonas vaginalis
Symptoms of Trich in women
Acute in 10%
Inflammation
Itching
Tenderness
Profuse frothy, creamy discharge
Symptoms of Trich in men
Mild, often self limiting
Urethritis or prostatitis
Transmission of Trich?
Sexual intercourse
Contaminated toilet articles
Toilet seats
During passage through the birth canal
Treament of Trich.
Metronidazole
What can women do to help suppress the infection?
Vinegar douches
Restores acid environment, organism can survive below pH 4.9
Drugs used with Intestinal and luminal protozoan infections
(Think of all the ones we just mentioned)
Iodoquinol
Paromomycin
Metronidazole
MOA of Iodoquinol (Diiodohydroxyquin)
Liberates iodine which is an active amebicide
PK of Iodoquinol
Not well absorbed from gut- helps w/effectiveness b.c. it sticks around
SE of Iodoquinol
Headache
Diarrhea
Nausea
Vomiting
Skin rashes
Puritis
Slight thyroid enlargement
High dose Iodoquinol can cause what serious side effects?
Loss of visual acuity
Optical atrophy
Blindness
What kind of antibiotic is Paromomycin? How can we use it?
Aminoglycoside
For intestinal amebiasis and intestinal cestode infections
MOA of Paromomycin
Acts on protein synthesis
PK of Paromomycin
Poorly absorbed from intestine
SE of Paromomycin
Diarrhea
Abdominal pain
Nausea or dizziness sometimes
**Can alter the bacterial population of the bowel, superinfection can be a problem
Metronidazole use
E.histolytica
T. vaginalis
G. lamblia
Anerobic bacteria- Clostridia and Bactreoides
MOA of Metronidazole
Acts as an electron sink to prevent terminal electron transport from reoxidizing NADH and NADPH- effective against anerobes and mircoanerobes

Can also be reduced to a form that can introduce DNA modifications
PK of Metronidazole
Given orally (available in suppository), well absorbed from GI tract
Eliminated by kidneys
SE of Metronidazole
GI upset
Metallic taste
Metronidazole + Alcohol
No!
No alcohol for at least 24 hours after drug get DISULFIRAM effect
Rare SEs of Metronidazole
Nervous system toxicity- weakness, paresthesias, vertigo, ataxia
Protozoan infections in AIDS
Cryptosporidiosis
Cyclosporiasis
Isosporiasis
Microsporidiosis
Pneumocystis
Toxoplasmosis
Toxoplasmosis cause? Who has it?
Toxoplasma gondii

About 10-15% of the population infected
*Nearly all cases are due to reactivation of latent infections once the person becomes immunocomprimised
Transmission of Toxo?
Eating undercooked meat containing cysts
Ingestion of oocyst in food
CONGENITAL INFECTION
Blood or organ transplant
What percentage of HIV people develop toxoplasmic encephalitis in the U.S.
10-20%
Treament of choice for Toxo
Pyrimethamine w/sulfadiazine
What must all pts taking pyrimethamine also take?
Folic acid supplements (leucorvin) to prevent bone marrow suppression, Pyrimethamine is a folate antagonist
What if the pt can't tolerate sulfadiazine?
Choices:
Pyrimethamine + clindamycin
Pyrimethamine + azithromycin
Pyrimethamine + atovaquone
Can pregnant women take Pyrimetamine?
Nope
Prophylactic treament of Toxo
For toxoplasma seropositive HIV pts w/low CD4
TMP/SMZ or pyrimethamine + dapsone + leucovorin
Symptoms of PCP infection
Pneumocystis most often seen in AIDS pts.
Shortness of breath, fever, non-productive cough
Probable transmission of PCP
Droplets
Treatment for PCP
TMP/SMZ
2nd line for PCP? Why will we be more apt to use these?
Pentamidine isethionate
*AIDS pts have a high incidence of adverse rxns to TMP/SMZ
Atovaquone
FDA approved for TMP/SMZ intolerant PCP patients
Prophylaxis of PCP
Inhalation of aerosolized Pentamidine
Drugs used to treat protozoan infections in AIDS pts?
Atovaquone
Folic acid antagonists
Pentamidine isethionate
Pyrimethamine w/sulfadiazine
TMP/SMZ
Atovaquone Uses
PCP
Toxoplasmosis
Microsporidiasis in AIDS pts
MOA of Atovaquone
Unknown
Inhibitory analogue of ubiquinone
PK of Atovaquone
Absorption
t1/2
Excretion
% bound
Not well absorbed, given w/fat to aid in absorption
Long t1/2 (2-3 days)
Excreted unchanged
99% bound to plasma proteins
SE of Atovaquone
Rash
Fever
Vomiting
Headache
Trimethoprim and pyrimethamine interfere w/what step of folic acid sythesis
Dihydrofolic acid--> Tetrahydrofolic acid
Sulfonamide blocks what step in folic acid synthesis
Pteridine + PABA--> Dihydropteric acid
Just for FYI the Folic acid synthesis cycle (abbreviated)
Pteridine + PABA-->
Dihydropteric acid-->
Dihydrofolic acid (+folic acid from food)--> Tetrahydrofolic acid
Uses of Pentamidine isethionate?
T. gambiense and rhodensiense
L. donovani
P. carinii
MOA of Pentamidine isethionate
Causes selective breaks in the kinetoplast mini-circle DNA of trypanosomes
Admin of Pentamidine isethionate
i.m. or i.v.
(Not well absorbed from GI)
PK of Pent. isethionate
Storage and excretion
Cross the BBB?
Stored in tissues, excreted unchanged
*Does not penetrate CNS (no use in late stage sleeping sickness)
Toxicity of Pentamidine isethionate (holy cow!)
Hypotension
Tachycardia
Dizziness or fainting
Headaches
Vomiting
Reversible hepatic and renal damage
Selectively toxic to pancreatic beta cells- hypoglycemia, can result in diabetes