Anthelmintic Agents
Two Types of Helminths Commonly Infecting Humans
- Nematodes or roundworms
- Pinworms, whipworms, threadworms, Ascaris, and hookworms
- Platyhelminthes or flatworms
- Cestodes (tapeworms) and flukes (schistosomes)
Measures to Control Infection
- Keep nails short
- Keep hands clean
- Frequent handwashing
- Shower in the morning
- Change and launder undergarments, bed linens, and pajamas daily
- Disinfect toilet seat daily
- Handwashing after using the bathroom
Tissue-Invading Worms
- Trichinosis
- Caused by ingestion of the encysted larvae of the roundworm, Trichinella spiralis, in undercooked pork
- Filariasis
- Infection of the blood and tissues of healthy individuals by worm embryos, injected by insects
- Schistosomiasis
- Infection by a fluke that is carried by a snail
Life Cycle of Schistosoma

Mebendazole (Vermox)
- Most commonly used of all of the anthelmintics
- Effective against pinworms, roundworms, whipworms, and hookworms
- Available in the form of a chewable tablet
- Few adverse effects
- Not metabolized in the body; most is excreted unchanged in the feces
- Should not be used during pregnancy
Pyrantel (Antiminth, Pin-Rid, Pin-X, Reeseās Pinworm)
- Oral drug effective against pinworms and roundworms
- Given as a single dose
- Poorly absorbed; excreted unchanged in the feces
- Not recommended for use during pregnancy and lactation
- Safety not established for children age <2 years
- Adverse effects may include GI side effects and diarrhea
Thiabendazole (Mintezol)
- Treats roundworm, hookworm, and whipworm infections
- Not the anthelmintic drug of choice (not as effective, more adverse effects)
- Best drug for treatment of threadworm infections
- Readily absorbed from the GI tract; reaches peak levels in 1 to 2 hours
- Metabolized in the liver and excreted in the urine
Albendazole (Albenza)
- Treats active lesions caused by pork tapeworm and cystic disease of the liver, lungs, and peritoneum caused by dog tapeworm
- Serious adverse effects
- Should be used only after causative worm is identified
- Poorly absorbed from the GI tract; reaches peak levels in about 5 hours
- Metabolized in the liver and primarily excreted in the urine
- Should not be used during pregnancy and lactation
Ivermectin (Stromectol)
- Effective against the nematode that causes onchocerciasis, or river blindness
- Used to treat threadworm disease or strongyloidiasis
- Readily absorbed from the GI tract; reaches peak plasma levels in 4 hours
- Completely metabolized in the liver with a half-life of 16 hours; excreted through the feces
- Should never be taken during pregnancy; used with caution during lactation
Praziquantel (Biltricide)
- Very effective in the treatment of a wide number of schistosomes, or flukes
- Taken in a series of three doses at 4- to 6-hour intervals
- Has relatively few adverse effects
- Rapidly absorbed from the GI tract; reaches peak plasma levels within 1 to 3 hours
- Metabolized in the liver with a half-life of 0.8 to 1.5 hours
- Excreted primarily through the urine
Anthelmintic Actions/Indications
- Affects metabolic processes that are different in worms than in human hosts or are not found in humans
- Causes death of the worm by interfering with normal functioning
Anthelmintic Contraindications
- Presence of known allergy to any of these drugs
- Lactation
- Pregnancy (in most cases)
- Caution should be used in the presence of renal or hepatic disease or severe diarrhea and malnourishment
Anthelmintic Adverse Effects
- Abdominal discomfort
- Diarrhea
- Pain
- Headache
- Dizziness
- Fever
- Chills
Anthelmintic Drug-to-Drug Interactions
- Theophylline = increased levels of theophylline
- Albendazole with dexamethasone increases the overall effect of the drug
Sites of Action of the Anthelmintic Drugs

Use of Anthelmintic Agents Across the Lifespan
Prototype Anthelmintic Agent
Drug/Dosage/Indication

Drug/Dosage/Indication

Nursing Considerations for Anthelmintic Agents
- Assessment (history and physical exam)
- Nursing diagnosis
- Implementation
- Evaluation