Anti Helminthic

Question 0

Albendazole

Answer 0

A benzimidazole
Immobilize parasite which then die, larycidal, ovicidal
For ascariasis (roundworm), enterobiasis (pinworm), hookworm, cutaneous & visceral larva migrans, intestinal capillariasis, gnathostomiasis, giardiasis, taeniasis, hydatid cysts, for neurocysticercosis use w corticosteroid
Adverse Effects: short term mild epigastric pain, diarrhea, nausea, headache & insomnia; long term use for hydatid cyst & cysticercosis fever, headache, ab pain, fatigue, alopecia, increased liver enzymes, pancytopenia

Question 1

Benzimidazole

Answer 1

Inhibits polymerization of tubulin into microtubules thus prevents parasitic growth (cell division). Inhibits mitochondrial fumarate reductase reducing glucose transport which prevents parasitic cellular division.
For broad spectrum nematode & cestode

Question 2

Mebendazole (Vermox)

Answer 2

Drug of choice for most common intestinal nematode infections in US
Give w fatty meal for better absorption

Question 3

Pyrantel pamoate

Answer 3

Neuromuscular blocking agent causing paralysis of parasite
For Alt to mebendazole for ascariasis, hookworm, pinworm; luminal parasite
Not effective against migratory stages in tissues or against ova
Adverse Effects: transient GI disturbance, drowsiness, headache, insomnia, rash, fever
Contraindicated in pregnancy & children younger than 2yrs

Question 4

Piperazine

Answer 4

Block ACh at neuromuscular junction causing paralysis of ascaris
For ascariasis only

Question 5

Diethylcarbamazine

Answer 5

Immobilizes microfilariae & alters their surface structure displacing them from tissues & making them susceptible to destruction by host defenses
For filariasis (eg Wuchereria bancrofti, Brugia malayi), tropical eosinophilia, Loa loa
Adverse Effects: fever, malaise, papular rash, headache, GI disturbance, cough, chest pain, muscle & joint pain, leukocytosis, retinal hemorrhage, encephalopathy, lymphangitis, lymphadenopathy
Contraindicated in hypertension, renal disease, lymphangitis

Question 6

Ivermectin

Answer 6

Acts on glutamate gated Cl channel receptors leading to Cl influx which causing hyperpolarization. Results in paralysis of parasite by potentiating inhibitory GABA-ergic transmission of signals in peripheral nerves
For Onchocerciasis (River blindness), filariasis, cutaneous larva migrans, strongyloidiasis, scabies, lice
Adverse Effects: corneal opacity, Mazzotti rxn due to killing of parasite (fever, headache, dizziness, somnolence, hypotension, tachycardia, peripheral edema), fatigue, GI disturbance
Contraindicated in use w other GABA-ergic drugs (barbiturates, benzodiazepines), meningitis, pregnancy category C, children under 5yrs

Question 7

Praziquantel

Answer 7

Disrupts the memb of schistosome that coats the parasite w host molecules causing rapid influx of Ca ions into parasite resulting in muscular tetany
For all schistosome species; beef, pork, fish, dwarf tapeworms

Question 8

Oxamniquine

Answer 8

For intestinal schistosomiasis of Schistosoma mansoni in Africa & South America

Question 9

Metrifonate

Answer 9

Organophosphorus cmpd that is an irreversible cholinesterase inhibitor
For urinary schistosomiasis

Question 10

Luminal amebicides

Answer 10

Diloxanide furoate, Lodoquinol, Paromomycin

Diloxanide furoate for asymptomatic amebiasis

Question 11

Metronidazole & Tinidazole

Answer 11

Undergoe reductive bio activation of the nitro group by ferredoxin to form reactive cytotoxic products
Usually used w luminal amebicide
Drug of choice in severe intestinal wall disease, in hepatic abscess, extra intestinal amebic disease, also used for trichomoniasis, giardiasis, Gardnerella vaginalis, anaerobic (C.difficile, B.fragilis), ulcers associated w H. pylori
Adverse Effects: Disulfiram like rxn, GI irritation, headache, dark urine, leukopenia, dizziness, ataxia