Name: helminth drugs and how they work
Uploaded: 2026-03-12T13:35:47.000Z
Duration: 1 min 15 s
Channel: JoVE

Gli agenti antihelmintici sono farmaci che eliminano gli elminiti parassiti, spesso colpendo le forme adulte, anche se alcuni influenzano gli stadi larvali o delle uova.Ad esempio, i farmaci pirazinoisochinochinolinico, come il praziquantel, mirano alle cellule tegumentali protettive del parassita.Il Praziquantel entra in queste cellule e provoca un rapido afflusso di ioni calcio attraverso i canali ionici.L'ingresso improvviso di calcio provoca una contrazione muscolare prolungata. Alla fine, il parassita diventa paralizzato nello stato contratto.Questa interruzione rende il tegumento poroso, esponendo le superfici interne e gli antigeni interni al sistema immunitario dell'ospite.Questi cambiamenti morfologici indeboliscono le difese del parassita, rendendolo più suscettibile agli attacchi immunitari.Di conseguenza, modulatori immunitari, come gli anticorpi, possono agire sugli antigeni del parassita esposti, migliorando il riconoscimento immunitario dell'ospite.Questa risposta immunitaria agisce in sinergia con il praziquantel, accelerando la eliminazione del parassita.

agenti anthelmintici

Anthelminthic Agents

I farmaci antihelmintici differiscono significativamente dalle terapie antiparassitarie che mirano ai protozoi, principalmente a causa delle differenze nella biologia dei parassiti. Mentre la maggior parte dei trattamenti protozoari agisce sulle cellule proliferanti, gli antihelmintici sono tipicamente diretti contro gli elmini maturi e non proliferativi. L'approccio terapeutico considera la dipendenza dell'elminto dalla coordinazione neuromuscolare, dal metabolismo del glucosio e dall'integrità microtubolare per la sopravvivenza, la riproduzione e la localizzazione all'interno dell'ospite. La maggior parte degli antihelmintici sfrutta queste vulnerabilità.Benzimidazoli: Alterazione della funzione dei microtubuli Benzimidazoli come albendazolo, mebendazolo, tiabendazolo e triclabendazolo sono agenti ad ampio spettro che compromettono la polimerizzazione della tubulina. Questa inibizione compromette la motilità dei parassiti, il metabolismo energetico e i processi riproduttivi. La loro efficacia comprende nematodi intestinali (ad esempio Ascaris, Trichuris), cestodi (ad esempio Taenia, Echinococcus) e alcuni trematodi (ad esempio, Fasciola). L'albendazolo inoltre manifesta attività contro la Giardia ed è un elemento chiave nelle strategie di somministrazione di massa di farmaci per la filariosi.Bloccanti neuromuscolari: Tetraidropirimidine e piperazine Il pamoato pirantel, un tetraidropirimidino, induce la depolarizzazione delle cellule muscolari nematodi attivando recettori colinergici, portando alla paralisi e all'espulsione. La dietilcarbamazina (DEC), un derivato della piperazina, immobilizza le microfilarie attraverso meccanismi poco definiti, tra cui alterazione del metabolismo dell'acido arachidonico e un aumento della pulizia immunitaria dell'ospite. La DEC è fondamentale nel trattamento della filariasi ed è sempre più utilizzata in regimi a dose singola.Modulatori dei canali ionici e agonisti del calcio L'ivermectina, un'avermectina, prende di mira i canali cloruro, causando iperpolarizzazione e paralisi. È efficace contro nematodi intestinali e filarie, riducendo in particolare i carichi microfilariari nell'oncocercosi. Il praziquantello, una pirazinoisoquinolina, agisce come agonista del calcio, aumentando il Ca2+ intracellulare nei trematodi e cestodi, il che porta a contrazioni muscolari e alterazioni del tegumento, esponendo gli antigeni alle risposte immunitarie dell'ospite.Disruptori mitocondriali e agenti secondari La niclosamide, un composto fenolico, disaccoppia la fosforilazione ossidativa nei cesodi, esaurendo le riserve di ATP e immobilizzando il parassita. Altri agenti secondari, tra cui ossamnichina, metrifonato e suramina, sono usati selettivamente per infezioni specifiche da trematodo e filari.Questa diversità mirata nei meccanismi evidenzia la complessità della biologia degli elminti e sottolinea la necessità di strategie antihelmintiche su misura.

Agenti Anthelmintici

Anthelmintic drugs differ significantly from antiparasitic therapies targeting protozoa, primarily due to differences in parasite biology. Whereas most ...

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helminth drugs and how they work

Helminth drugs work by attacking the weak points of parasitic worms. These anthelmintic medicines are different from drugs used against protozoa, because they are usually aimed at mature helminths rather than fast-dividing cells. They target the worm’s movement, glucose use, and microtubule structure to stop survival, reproduction, and location inside the host.

Benzimidazoles are broad-spectrum anthelmintics that block tubulin polymerization, which means they interfere with microtubules, the cell structures that help maintain shape and movement. Drugs in this group include albendazole, mebendazole, thiabendazole, and triclabendazole. By disrupting microtubule function, they reduce motility, energy metabolism, and reproduction in intestinal nematodes such as Ascaris and Trichuris, in cestodes such as Taenia and Echinococcus, and in some flukes such as Fasciola.

Albendazole also has activity against Giardia and is used in mass drug administration programs for filariasis. Other anthelmintics act on the worm’s nervous system and muscles. Pyrantel pamoate, a tetrahydropyrimidine, activates cholinergic receptors in nematode muscle cells and causes depolarization, which leads to paralysis and expulsion.

Diethylcarbamazine, or DEC, is a piperazine derivative that immobilizes microfilariae, the early blood stages of filarial worms. Its exact action is not fully defined, but it may involve altered arachidonic acid metabolism and better clearance by the host immune system. DEC is important in filariasis treatment and is increasingly given in single-dose regimens.

Ivermectin and praziquantel work through different mechanisms. Ivermectin, an avermectin, acts on chloride channels and causes hyperpolarization and paralysis, especially in intestinal nematodes and filariae, and it helps lower microfilarial loads in onchocerciasis. Praziquantel, a pyrazinoisoquinoline, acts as a calcium agonist in trematodes and cestodes, causing muscle contraction and damage to the tegument, the worm’s outer covering, which exposes antigens to host immune responses.

Niclosamide works in another way by uncoupling oxidative phosphorylation in cestodes, which drains ATP and immobilizes the parasite. Other selective agents, including oxamniquine, metrifonate, and suramin, are used for specific trematode and filarial infections. Together, these drug classes show how different helminths require tailored treatment strategies based on their biology.

Helminth Drugs and How They Work

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Helminth drugs work by attacking the weak points of parasitic worms. These anthelmintic medicines are different from drugs used against protozoa, because they are usually aimed at mature helminths rather than fast-dividing cells. They target the worm’s movement, glucose use, and microtubule structure to stop survival, reproduction, and location inside the host. Benzimidazoles are broad-spectrum anthelmintics that block tubulin polymerization, which means they interfere with microtubules, the...

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key terms and concepts

Learn how anthelmintic drugs treat helminths by targeting microtubules, muscle control, ion channels, calcium signals, and parasite energy use.

Helminth Drugs and How They Work | JoVE K12

JoVE Core Microbiology provides an engaging introduction to the microbial world and its influence on health, industry, and the environment. This comprehensive collection covers key concepts such as microbial structure, metabolism, genetics, and ecology. It introduces essential laboratory techniques and microscopy methods through visually engaging animations. Corresponding scientist-in-action videos bridge classroom concepts with real-world research and applications.

microbiology

Helminth Drugs and How They Work

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