Exam 9: Antihelminthic and Antiprotozoal Drugs Flashcards
Name 3 antihelminthic drugs?
- Albendazole
- Pyrantel
- Praziquantel
Name 4 antiprotozoal drugs?
- Metronidazole
- Iodoquinol
- Paromomycin
- Nitazoxanide
What are 2 drugs used to treat pinworm (Enteriobius vermicularis)?
- Albendazole
2. Pyrantel
What are 2 considerations when treating pinworm?
- treatment works well when the patients adheres to strict personal hygiene standards
- Treat both the patient and their family members
(Remember, treat with Albendazole and Pyrantel)
What drug is used to treat asymptomatic or mild Ascariasis? Severe?
Mild/Asymptomatic: Albendazole
Severe: Pyarntel pamoate
What drug is used to treat Necator americans (hookworm)?
Albendazole
What drug is used to treat Taenia solium and saginata?
Praziquantel
What is an adjunctive therapy you can use when treating Taenia solium with Praziquantel?
Treatment can result in release of embryos from eggs and result in cysticercosis, so you may want to treat with a purgative (laxative) like Magnesium sulfate.
What 2 antihelminthic drugs are used to treat Neurocysticercosis?
Albendazole and Praziquantel
What non-antihelminthic drug is used in the treatment of Neurocysticercosis?
Dexamethasone
give it 1-2 days before treatment and 4-7 days after treatment ends.
What is a pharmacokinetic consideration with Albendazole?
It has to be metabolized in the liver to Albendazole sulfoxide to be active.
What is the mechanism of Albendazole?
Binds to Beta-tubulin, causing inhibition of microtubule polymerization and therefore a decrease in microtubule-dependent glucose uptake by the parasite.
Why is Albendazole selective against helminths?
It does not bind well to mammalian Beta-tubulin
What are adverse effects of Albendazole?
GI stuff (most frequent)
Teratogenic
Hepatotoxicity/Increased liver enzymes
Leukopenia (perform blood counts every 2 weeks)
What is the mechanism of Pyrantel?
Activation of cholinergic nicotinic receptors in nematode muscles, causing a depolarizing neuromuscular blockade (human receptors are different, so it doesnt have this effect)
What are adverse effects of Pyrantel?
GI problems (most frequent)
Headache, dizziness, drowsiness
Use with caution in patients with liver failure, pregnant women, and kids under 2.
What is the mechanism of praziquantel?
Causes an increase in Ca+ influx, inducing muscle contracture and paralysis, dislodging the suckers
(Little effect on human muscle)
What are two types of bugs that Praziquantel can be used for?
Schistosomes (trematodes)
Tapeworms (cestodes)
Adverse effects of Praziquantel?
Dizziness, drowsiness, headache, AMS (most common)
GI problems
Increased liver enzymes
Low grade constitutional symptoms several days after therapy.
Avoid in pregnancy (caused abortions in rats)
Where can intestinal Entamoeba infections spread and cause?
Liver, abscesses
What 2 drugs are used to treat asymptomatic carriers of Entamoeba histolytica?
Iodoquindol and Paromomycin
What drug is used to treat symptomatic Entamoeba infections?
Metronidazole, followed by Iodoquinol or Paromycin
What 2 drugs are preferred for Giardiasis?
Metronidazole and Nitazoxanide
Who gets treated with Trichomoniasis?
Infected woman and her sexual partner(s) to prevent recurrence
What drug is used to treat Trichomoniasis?
Metronidazole
What two drugs are used to treat Cryptosporidium?
Paromomycin and Nitazoxamide
What is the mechanism of Metronidazole?
Inhibits DNA synthesis
Nitro group gets reduced, binds to intracellular macromolecules like DNA, inhibits DNA synthesis.
Adverse effects of Metronidazole?
Disulfiram-like reaction with alcohol
Nausea, headache, metallic taste
Carcinogenic in first trimester
Where is Iodoquinol effective?
GI tract, because it’s not well absorbed.
Adverse effects of Iodoquinol?
Neurotoxicity (optic neuritis, loss of vision)
GI upset
Where is Paromomycin effective?
GI tract, because it’s not well absorbed.
What is the mechanism of Paromomycin?
It is an aminoglycoside
Binds to the 30S ribosomal, inhibiting protein synthesis
What are adverse effects of Paromomycin?
Ototoxicity, nephrotoxicity (aminoglycoside)
Go side effects
What is a pharmacokinetic consideration of Nitazoxanide?
Must be hydrolyzed into an active form (tizoxanide)
What is the mechanism of Nitazoxanide?
Inhibits pyruvate:ferredoxin 2-oxidoreductase enzyme dependent electron transport reaction
Interfering with anaerobic energy metabolism
What are uses of Nitazoxanide?
Diarrhea caused by Cryptosporidium in immunocompetent children 1-11, adolescents, and adults.
What is an advantage of Nitazoxanide over Metronidazole?
Doesnt have mutagenic/carcinogenic effects
