Anthelmintics are medicines used to treat infections caused by parasitic worms (helminths). These parasites commonly infect the intestine but may also invade tissues such as the liver, lungs, and muscles. Deworming drugs help eliminate or immobilize these worms so that the body can remove them easily.
Types of Helminths
Helminths are broadly classified into:
- Nematodes (Roundworms) – e.g., Ascaris, Hookworms, Enterobius
- Cestodes (Tapeworms) – e.g., Taenia, Echinococcus
- Trematodes (Flukes) – e.g., Schistosoma, Fasciola
General Mechanism of Anthelmintic Drugs
Most anthelmintic agents act by one or more of the following mechanisms:
- Paralyzing the worms
- Blocking glucose uptake or energy production
- Damaging the worm’s outer surface (tegument)
- Inhibiting worm enzymes or reproduction
Major Anthelmintic Drugs and Their Actions
1) Albendazole
Action: Interferes with microtubule formation in worms and blocks glucose uptake, leading to energy depletion.
Uses: Broad-spectrum; effective for roundworms, hookworms, tapeworms, and tissue infections such as cysticercosis.
2) Mebendazole
Similar to albendazole.
Uses: Enterobiasis (pinworm), ascariasis, hookworm infections.
3) Pyrantel Pamoate
Action: Acts as a neuromuscular blocker, causing paralysis of worms.
Uses: Pinworms, roundworms, and hookworms.
4) Piperazine
Action: Produces flaccid paralysis in roundworms so they are expelled naturally.
Uses: Ascariasis and enterobiasis.
5) Levamisole
Action: Stimulates worm muscle contractions leading to paralysis.
Uses: Roundworm infections.
6) Diethylcarbamazine (DEC)
Action: Alters the surface of microfilariae and increases susceptibility to immune destruction.
Uses: Filariasis caused by Wuchereria bancrofti.
7) Ivermectin
Action: Enhances inhibitory neurotransmission in worms.
Uses: Strongyloidiasis and onchocerciasis.
8) Praziquantel
Action: Increases calcium permeability in worm cells leading to paralysis and detachment.
Uses: Tapeworm and fluke infections.
9) Niclosamide
Action: Inhibits ATP generation in tapeworms.
Uses: Intestinal tapeworm infections.
Clinical Uses of Anthelmintics
- Intestinal worm infections such as roundworms, hookworms, and pinworms
- Tapeworm infections caused by Taenia species
- Tissue helminth infections including cysticercosis and hydatid disease
- Filariasis and onchocerciasis (river blindness)
Side Effects
Most anthelmintics are well tolerated. Some may cause:
- Nausea and abdominal discomfort
- Dizziness
- Headache
- Occasional allergic reactions
Detailed Notes:
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