Antiparasitics Flashcards
symptoms of amebiasis
mild diarrhea to fulminating dysentery
form of entamoeba histolytica and where they survive
cysts (survive outside the body)
trophozoite (do not survive outside body)
what are mixed antamebics and name them
Metronidazole and Tinidazole
they are active against luminal and systemic disease
what happens to metronidazole once it is absorbed aka mechanism of the drug
nonenzymatically reduced by reacting with ferredoxin –> production of cytotoxic compounds –> bind to protein and DNA –> CELL DEATH
adverse effects of metronidazole
- Disulfiram like reaction
- Dark colored urine
- Unpleasant metallic taste
- GI distress
what is Tinidazole used for and compare it to metronidazole
-better tolerated than metronidazole and has shorter duration of effects
used for amebiasis, amebic liver abscesses, giardiasis, trichomoniasis
what are the luminal antiamebics
Diloxanide Furoate
Iodoquinol
Paromomycin
adverse effects of diloxanide furoate
mild GI distress
adverse effects of Iodoquinol
if used long term –> optic neuritis
dose related peripheral neuropathy
mechanism of paromomycin
aminoglycoside antibiotic that causes cell membrane to leak by interfering with bacterial protein synthesis by binding to 30S
adverse effect of paromomycin
GI distress and diarrhea
what are the systemic antiamebics and what they are used to treat
Chloroquine
Emetine
Dehydroemetine
used for treating liver abscesses or intestinal wall infections
mechanism of chloroquine
it eliminates trophozoites in liver abscesses
mechanism of emetine and dehydroemetine
inhibits protein synthesis by blocking ribosomal movement along messenger RNA
adverse effects of emetine and dehydroemetine
Pain at site of injection
Cardiotoxicity
Neuromuscular Weakness
what are the three helminths and describe them
Nematodes - elongated roundworms that cause infection of intestine, blood, and tissue
Trematodes - leaf shaped flatworms: liver, intestinal, or blood flukes
Cestodes - flat, segmented bodies that attach to host’s intestines
how do antihelminths works
- locally to expel worms from GI tract
- systemically to eradicate adult helminths or developmental forms
what are the benzimidazoles and a common contraindication they all share
Albendazole
Mebendazole
Thiabendzole
Pregnancy
mechanism of Albendazole
inhibits microtubule synthesis and glucose uptake –> reduction of ATP production –> worm immobilization –> death
what is Albendazole used to treat
cestodal infections like
- Cysticercosis (Tania Solium)
- Hyatid disease (Echinococcus)
adverse of albendazole
inflammatory responses to dying parasites in CNS
-headache, hyperthermia, vomiting, convulsions
contraindications of albendazole
pregnancy and children under 2
mechanism of mebendazole
inhibits formation of helminths microtubules by irreversibly blocking glucose uptake –> parasites expelled in feces
clinical applications of mebendazole
Whipworm - Trichuris
Pinworm - Enterobius Vermicularis
Hookworms - Necator americanus and Anyclostoma duodenale
Roundworms - Ascaris
contraindication of mebendazole
pregnancy
cautious in those under 2 and those with cirrhosis
mechanism of thiabendazole
affects microtubular aggregation
clinical applications of thiabendazole
Strongyloides Stercoralis (threadworm)
Cutaneous Larva Migrans
Trichinosis
adverse effects of thiabendazole
Stevens Johnson rash
Erythema Multiforme
CNS disturbances
mechanism of Ivermectin
GABA agonist –> Cl influx –> hyperpolarization of nerve/muscle cell –> paralysis of parasite –> death of parasite
clinical application of ivermectin
Strongyloides (STI)
Onchera Volvulus
Cutaneous Larva Migrans
adverse effect of Ivermectin and contraindication
Mazotti like reactions with onchoceriasis
-fever, somnolence, dizziness, hypotension
-Contraindicated in pregnancy and meningitis (may cross BBB)
What is Piperazine used to treat and its mechanism
GABA agonist that causes expulsion of warm by peristalsis –> used to treat pinworms and roundworms
contraindications of piperazine
seizure disorders
MOA of Pyrantel Pamoate and clinical application
depolarizing, neuromuscular blocker
round worms, pinworms, hookworms
MOA of diethylcarbamazine and clinical application
immobilizes microfilariae and makes them susceptible to host defenses
lymphatic filariasis, loiasis, and tropical eosinophilia
what are most diethylcarbamazine adverse effects due to and what is most common
due to host responses following damage or death of parasite
leukocytosis
MOA of doxycycline and what it is used for
indirectly kills wolbachia (intracellular bacterial symbiont of filarial parasites)
Wuchereria Bancrofti and Onchocerciasis
MOA of pranziquantel and clinical applications
increases permeability of cell membrane to calcium –> contracture and paralysis of worm –> detachment of suckers from blood vessel walls
schistosomiasis and most trematode and cestode infections
adverse effects of pranziquantel and contraindications
drug interaction of CYP450
contraindicated in pregnancy, nursing mothers, and treatment of ocular cysticercosis
MOA and clinical application of bithionol
inhibition of helminth’s electron transport chain
drug of choice for fasciolosis (sheep liver fluke)
MOA and clinical app of niclosamide
inhibits mitochondrial phosphorylation of ADP –> lethal to cestode scolex and segments of cestode but not ova
most cestode infections
what do you give before administering niclosamide and what do you avoid
give laxative to purge all dead segment of cestode in order to preclude digestion of and liberation of ova
avoid alcohol within a day of giving dose
what are the antihelminths
PPPin bamDD
Piperazine Praziquantel Pyrantel Pamoate Ivermectin Niclosamide
Bithionol Albendazole Mebendazole Diethylcarbamazine Doxycycline
what is pentamidine used for
hemolymphatic stage of trypanosomiasis and pneumocystis jirovecii infections
used for treatment of toxoplamosis
Pyrimethamine + Clindamycin or Sulfadiazine + folinic acid
treatment of leishmaniasis of all stages
sodium stibogluconate or amphoteracin B
uses to treat African Trypanosomiasis (sleeping sickness)
Suramin or Melarsoprol
what is co-trimoxazole used for (trimethoprim-sulfamethoxazole)
pneumocystic jirovecii infections
