Antiprotozoals and Anthelminthics Flashcards
Amebiasis etiology
Entamoeba histolytica
Amebiasis transmission
contaminated water/food or direct contact.
Amebiasis life cycle
two forms: cysts are infectious and trophozoites invade and replicate in the tissues, usually the liver (abscess forming) and intestinal wall (diarrhea). Those that stay in the lumen are asymptomatic.
Giardiasis Etiology
Giardia lamblia. Most common cause of diarrhea in north america. Beaver is a resevoir.
Giardiasis transmission
contaminated water/food or direct contact
Trichomoniasis etiology
trichomonas vaginalis
Trichomoniasis transmission
STI. Men can be asymptomatic carriers.
Trichomoniasis symptoms
vaginitis with frothy yellow discharge
Toxoplasmosis etiology
Toxoplasm gondii. Commonly found in cat feces.
Toxoplasmosis fetal infection
heart problems, hydrocephalus and retinochorioiditis.
Pneumocystosis etiology
Pneumocystis jirovecii. Yeast-like fungus. Major cause of death in AIDS patients.
E. hystolytica DOC
Metronidazole with a luminal amebicide (Iodoquinol, Paromomycin or tetracyline/erythromycin)
Giardia lamblia DOC
Metronidazole
Trichomoniasis vaginalis DOC
Metronidazole
Toxoplasma gondii DOC
Pyrimethamine + sulfadiazine +folinic acid
Pneumocystis jirovecii DOC
Bactrim + folinic acid
Tissue amebicides ( 3)
Metronidazole, tinidazole, emetine/dehydroemitine
Luminal amebicides (4)
Iodoquinol, Paromomycin, tetracyline or erythromycin
Metronidazole (Flagyl) uses
DOC for E. histolytica, G. lamblia, and T. vaginalis.
Metronidazole MOA
Pro-drug that is non-enzymatically reduced by reacting with ferredoxin forming unstable metabolites that damage DNA.
Metronidazole Toxicity
metallic taste, disulfiram-like reaction.
Tinidazole (Tindimax) uses
Similar to metronidazole but not as effective. Used for E. histolytica, G. lamblia, and T. vaginalis.
Emetine + Dehydroemetine (mebadin) uses
Alternative to metronidazole and Tinidazole but so toxic used sparingly for severe or systemic E. histolytica.
Mebadin (emetine + dehyrdroemetine) kinetics
subcutaneous injection. Tissue amebicide. Need CDC permission to use.
Mebadin toxicity
Cardiotoxic, serious GI effects, teratogenicity.
Mebadin contraindications
cardiac or renal disease. pregnancy.
Iodoquinol (yodoxin) uses
Luminal trophozoites/cysts of E. histolytica. Also in combo with metronidazole.
Iodoquinol toxicity
high iodine content (thyroid enlargement), blindness.
Paromomycin (Humantin) uses
Luminal amebicide. Used for asymptomatic amebiasis, giardiasis, vaginalis or in combination with metronidazole.
Antibiotics as antiprotozoals
tetracycline and erythromycin. Alternate luminal drug for amebiasis and giardiasis. Can be used in combo with metronidazole. MOA: inhibit protein synthesis and normal flora (food source).
Pyrimethamine + sulfadiazine (Daraprim) uses
DOC for toxoplasma gondii. Administered with folinic acid to decrease side effects.
Trimethoprim + sulfamethoxazole (bactrim) uses
DOC for pnuemocystosis (P. Jirovecii).
Bactrim toxicity
bone marrow suppression (cytopenia), hypersensitivity reactions.
Pentamidine (pentam) uses
effective against P. jirovecci used in those that can’t tolerate bactrim.
Pentamidine MOA
inhibits DNA replication
pentamidine kinetics
IM (active infections) nebulizer (prophylaxis).
Pentamidine toxicity
hypotension, arrhythmias, hypoglycemia
Roundworms
Nematodes. Contaminated food (improperly cooked), daycares and crowed areas with poor sanitation.
Tapeworms
Cestodes. Beef, fish and pork that is improperly cooked.
Flukes
Trematodes. blood flukes are called schistosomes
Pyrantel Pamoate (antiminth) uses
Roundworm (nematodes). Available OTC.
Pyrantel Pamoate (antiminth) MOA
Cholinesterase inhibitor. Depolarizes the NMJ blockade.
Ivermectin (mectizan) uses
Roundworm (nematodes). Broad spectrum.
Ivermectin (mectizan) MOA
paralyzes the worm so it detaches. Intensifies the GABA mediated transmission in the nerves.
Filaria infections DOC
Ivermectin (mectizan)
Praziquantel (biltricide) uses
Tapeworms (cestodes). Oral, well absorbed for systemic infections. Can also be used for trematodes (flukes).
Schistosomes DOC
Praziquantel (biltricide)
Praziquantel (biltricide) MOA
increases calcium permeability resulting in contraction/paralysis leading to dislodgement.
Bithionol (Bitin) uses
Flukes (trematodes). Oral, absorbed in the GI tract.
Bithionol (Bitin) MOA
uncouples oxidative phosphorylation