Antiparasitic Flashcards
Quinine
32-01-
Antiparasitic - Antimalarial (Blood Schizonticide)
Tx: Severe acute attacks (rx of choice, rapid onset of action), All four malarial parasites (blood), Alternative for chloroquine-resistant P. falciparum
Side Effects: Cinchonism (HA, visual disturbance, dizziness, tinnitus), Cardiac effects similar to quinidine, GI (N/V, irritation
)Mechanism: Similar to chloroquine
Pharmacology: Form = oral only, for IV use quinidine (isomer)
Mebendazole
32-01-08
Antiparasitic - Nematode (Roundworm)
Tx: Intestinal roundworms, Kills some ova
Side Effects: Low systemic toxicity
Pharmacology: Poorly absorbed (targets GI)
Albendazole
32-01-08
Antiparasitic - Nematode (Roundworm) and Cestode (Tapeworm)
Tx: Echinococcus (hydatid cyst disease), Unlabeled use for cutaneous larval migrans (“disseminated” dog or cat hookworm, cannot complete life cycle in human, tracks under skin before dying), Neurocysticercosis (rx of choice to treat NOT prevent)
Side Effects: Elevated hepatic enz, HA, GI (N/V, ab pain)
More systemic toxicity than mebendazole and pyrantel pamoate (both rx poorly absorbed)
Pharmacology: Metabolite well distributed
Thiabendazole
32-01-08
Antiparasitic - Nematode (Roundworm)
Tx: Strongyloides, Cutaneous larval migrans (“disseminated” dog or cat hookworm, cannot complete life cycle in human, tracks under skin before dying)
Side Effects: N/V, Dizziness, Higher incidence of systemic toxicity than albendazole
Pharmacology: Forms = oral (rapidly absorbed), topical (if infxn limited)
Pyrantel pamoate
32-01-08
Antiparasitic - Nematode (Roundworm)
Tx: Hookworm, Pinworm (OTC = Pin-X), Roundworm
Narrower spectrum than Mebendazole
NOT for whipworm (Trichuris)
Side Effects: Mild GI
Pharmacology: Poorly absorbed (targets GI)
Paromomycin sulfate
32-01-15
Antiparasitic - Cestode (tapeworm)
Tx: 3rd choice cestode infxn for pts who cannot tolerate other rx (disadvantage = can release viable ova)
32-01-33
Antiparasitic - Luminal Amebicide
Tx: Amebic dysentary (used alone for asymptomatic infxn, given with tissue amebicide for symptomatic infxn)
Side Effects: GI (N/V/D, epigastric pain)
Mechanism: Aminoglycoside that inhibits protein synthesis
Pharmacology: Form = oral (poor absorption, low incidence of systemic side effects)
Chloroquine
32-01-18
Antiparasitic - Antimalarial (Blood schzonticide)
Tx: Malarial prophylaxis (prevents attacks of all 4 species of malaria if sensitive) and treatment (eradicate Plasmodium malariae and rx-sensitive falciparum, also targets blood schizonts of P. vivax or ovale)NOT liver hypnozoites
Side Effects: Well tolerated (short term use), visual impairment (extended use)
Mechanism: RBC’s with parasite concentrate rx (weak base at physiological pH = sig uncharged) into acidic vacuoles inside malarial parasite due to pH dependent distribution and inhibits heme detoxification that polymerizes heme into non-toxic hemazoin, allowing heme to accumulate to toxic levels (forms free radicals, damages membrane, inhibits protease). Malarial parasite feeds on Hb in RBC, converting Hb to AA (for energy and proteins) and heme, which can form reactive oxygen species (redox active).
Praziquantel
32-01-12
Antiparasitic - Trematode (Fluke) and Cestode (Tapeworm)
Tx: Schistosoma (rx of choice), Some activity against other trematodes, Taenia solium (pork tapeworm, kills BOTH adults and eggs = PREVENT cysticercosis) Good activity for many cestodes (unlabeled use)
Side Effects: Well tolerated, GI (ab discomfort, nausea)
Trematodes infect internal organs (blood, lung, liver)
Mefloquine
32-01-
Antiparasitic - Antimalarial (Blood schizonticide)
Tx: Chloroquine-resistant Plasmodium falciparum and some vivax, Prophylaxis in chloroquine-resistant areas
Side Effects: Contraindicated in epilepsy (increase seizure incidence) or psychiatric disorders (no longer controlled), High incidence of CNS effects (DNNTK psychosis, hallucination, dysphoria, nightmares, lead to suicide)
Mechanism: Similar to chloroquine
Atovaquone + proguanil
32-01-24
Antiparasitic - Antimalarial (Blood schizonticide)
Tx: Chloroquine-resistant P. falciparum (prevention and tx)
Side Effects: Well tolerated, NO CNS, GI (N/V/D), Rash
Mechanism: Both rx block pyrimidine synthesis
Proguanil inhibits malarial dihydrofolate reductase, blocking folate (TH4) synthesis and ultimately pyrimidine synthesis
Pharmacology: Cannot give either rx alone (resistance develops)
Doxycycline
32-01-29
Antiparasitic - Antimalarial (Blood schizonticide)
Tx: Multi-rx resistant P. falciparum (in combo with quinine or atovaquone), Prophylaxis of chloroquine-resistant P. falciparum (single-rx therapy)
Mechanism: Depresses dehydroorotate dehydrogenase (DHOD), interfering with pyrimidine synthesis
Primaquine
32-01-30
Antiparasitic - Antimalarial (Liver hypnozoites)
Tx: Radical cure or terminal prophylaxis of P. vivax and ovale (used in conjunction with blood schizonticide), Pneumocystis jiroveci (carinii) pneumo in AIDS pts with clindamycin (2nd line therapy after TMP/SMX)
Side Effects: Hemolytic rxns in pts with G6P dehydrogenase deficiency
Iodoquinol
32-01-33
Antiparasitic - Luminal Amebicide
Tx: Amebic dysentary (used alone for asymptomatic infxn, given with tissue amebicide for symptomatic infxn)
Side Effects: Short term use well tolerated, GI symptoms, Contraindicated in iodine hypersensitivity
Metronidazole
32-01-
Antiparasitic - Tissue Amebicide
Tx: Amebic dysentary WITH symptoms (given with luminal amebicide)
Mechanism: Eliminate organisms in bowel wall, liver, other extra-intestinal tissues
Antiparasitic - Protozoal Diseases
Tx: Giardia lamblia (rx of choice), Trichomonas vaginalis
Nitazoxanide
32-01-37
Antiparasitic - Protozoal Diseases
Tx: Giardia lamblia (alternative), Cryptosporidium parvum
Side Effects: GI (diarrhea, nausea, ab pain)
Mechanism: Inhibits pyruvate:ferredoxin oxidoreductase, disrupting anaerobic energy metabolism (reduce nitro group to generate radical, diff mech from metronidazole)
