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Chemotherapeutic Agents Nursing Pharmacology

Anthelmintic Agents

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

Life Cycle of Shistosomo
Life Cycle of Shistosomo

 

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, Reeseā€™s 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

Sites of Action of the Anthelmintic Drugs
Sites of Action of the Anthelmintic Drugs

 

 

Use of Anthelmintic Agents Across the Lifespan

Use of Anthelmintic Agents Across the Lifespan
Use of Anthelmintic Agents Across the Lifespan

Prototype Anthelmintic Agent

Prototype Antelmintic Agent
Prototype Antelmintic Agent

Drug/Dosage/Indication

Drug/Dosage/Indication
Drug/Dosage/Indication

Nursing Considerations for Anthelmintic Agents

  • Assessment (history and physical exam)
  • Nursing diagnosis
  • Implementation
  • Evaluation

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