Helminths (worms) commonly infect the human intestine and other body tissues, especially in areas with poor sanitation. Anthelmintic drugs are medicines used to kill or expel these worms. They act through different mechanisms such as paralyzing the worms, damaging their structure, or interfering with their nutrient uptake.
Types of Helminths
Human helminths are broadly classified into:
- Nematodes (roundworms)
- Cestodes (tapeworms)
- Trematodes (flukes)
Major Anthelmintic Drugs
1. Albendazole
One of the most widely used broad-spectrum anthelmintics.
Mechanism
Albendazole blocks glucose uptake in worms and damages their structure, causing death.
Uses
- Roundworms (Ascaris)
- Hookworm
- Whipworm
- Pinworm
- Tapeworms
- Hydatid cyst disease
- Neurocysticercosis
Side Effects
- Nausea
- Abdominal discomfort
- Rare liver enzyme elevation
2. Mebendazole
Similar to albendazole; used mainly for intestinal worms.
Uses
- Roundworms
- Pinworms
- Hookworms
3. Pyrantel Pamoate
A safe and commonly used dewormer, especially for children.
Mechanism
Paralyzes worms by blocking neuromuscular activity, causing them to be expelled naturally.
Uses
- Pinworm infection
- Roundworms
- Hookworms
Side Effects
- Mild nausea
- Dizziness
4. Piperazine
Causes paralysis of worms by blocking nerve transmission.
Uses
- Roundworm infections
- Pinworms
5. Ivermectin
Highly effective for several parasitic infections.
Mechanism
Binds to parasite nerve channels, causing paralysis and death.
Uses
- Strongyloidiasis
- Onchocerciasis (river blindness)
- Scabies
- Lice
Side Effects
- Low blood pressure (rare)
- Dizziness
6. Praziquantel
The drug of choice for fluke and tapeworm infections.
Mechanism
Increases calcium permeability in worms, causing paralysis and death.
Uses
- Schistosomiasis (blood flukes)
- Liver flukes
- Tapeworms
7. Niclosamide
A drug specifically used for tapeworm infections.
Mechanism
Blocks energy production in tapeworms.
Uses
- Beef, pork, and fish tapeworms
General Symptoms of Helminth Infections
- Abdominal pain
- Loss of appetite
- Weight loss
- Itching around the anal region (pinworm)
- Malnutrition in chronic infections
Deworming Schedules
Single-Dose Deworming
- Albendazole 400 mg once
- Pyrantel pamoate (dose according to body weight)
Special Conditions
- Hydatid disease – prolonged albendazole therapy
- Neurocysticercosis – albendazole + steroids
Precautions
- Avoid in early pregnancy (albendazole/mebendazole)
- Check for G6PD deficiency in some therapies
- Ivermectin not recommended for children under 15 kg
Detailed Notes:
For PDF style full-color notes, open the complete study material below: