Antihelminthics Flashcards
Most common helminthic infection in US
Enterobiasis (pinworm)
What drug is a benzimidazole?
Albendazole
MOA of albendazole
- Inhibit polymerization of parasite B-tubulin
- prevent formation of cytoplasmic microtubules
- disrupt motility and uptake of glucose (slow death)
- best with high fat meal
- first pass metabolism to active form
Albendazole uses
- cestodes
- roundworms
- pinworms
Adverse reactions of albendazole
- generally well tolerated
- teratogenic effects
- long term —> liver toxicity (liver function tests)
- bone marrow suppression
Which antihelminths should be avoided in pregnancy?
Albendazole
Ivermectin
Neurocysticercosis
From undercooked pork contaminated with taenia solium (tapeworm eggs)
Cysts in brain can cause seizures
MOA of praziquantel
- increase permeability of trematode and cestode cell membranes to calcium —> paralysis, dislodgement, death
Praziquantel uses
- drug of choice for schistosomiasis
- other trematode and cestode infections
Drug of choice for schistosomiasis
Praziquantel
Alternative to albendazole for cysticercosis
Praziquantel
Adverse reactions of praziquantel
- generally well tolerated
- not clear whether symptoms are drug related or due to release of proteins from dying worms (fever, pruitis, rash)
Roundworm infection
Ascariasis
Hookworm
Toxocariasis
Cestode infection
Neurocysticercosis
Hydatid disease
MOA pyrantel pamoate
- depolarizing neuromuscular blocking agent
- effective only within in GI
- persistent activation of parasite nicotinic Ach receptors and inhibition of AChE —> spastic paralysis —> expulsion of worms
Alternative to albendazole for ascariasis and enterobiasis
Pyrantel pamoate
What antihelminthic agent is OTC?
Pyrantel pamoate
Pinworm infection
Denterobiasis
Adverse reactions of pyantel pamoate
- generally well tolerated
- will produce NM blockade if given parenterally
MOA ivermectin
- immobilization of worms by tonic muscle paralysis
- activate glutamate-gated Cl channels
- hyperpolarization of cell membrane
- P-glycoprotein efflux transporter pumps drug out of mammalian CNS
Ivermectin uses
- nematode and arthropods infections in vet medicine
- onchocerciasis, lymphatic filariasis and intestinal nematodes in humans
- scabies and head lice
Onchocerciasis
River blindness
Adverse reactions of ivermectin
- generally well tolerated
- Mazzotti recation
- Teratogenic
Mazzotti reaction
In onchocerciasis
Pruitis, rash, fever, lymphedema —> due to immune reaction to dying worms
Drug for cestodes (tapeworm)
Praziquantel
Drug for trematodes (flukes)
Praziquantel
Drug for nematodes (pork roundworm)
Albendazole
Drug for nematodes (filariae)
Ivermectin
Drug for nematodes (pinworm)
Benzimidazoles or pyrantel pamoate
Drug for nematodes (hookworm)
Albendazole
Drug for nematodes (whipworm)
Albendazole
Drug for nematodes (threadworm)
Ivermectin
Enterobiasis
Pinworm
Most common infection in US
Albendazole pregnancy?
No!
