McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 1 3  Anthelmintic agents

ANTHELMINTICS The anthelmintic drugs (see Table 13.2) act on meta­ bolic pathways that are present in the invading worm but are absent or significantly different in the human host. Anthelmintic drugs include albendazole

( Eskazole , Zentel ), ivermectin ( Stromectol ), meben- dazole ( Ridworm, Vermox ), praziquantel ( Biltricide ) and pyrantel ( Anthel, Combantrin ). Box 13.2 includes information about use of these drugs across the lifespan. See the Critical thinking scenario for a case study of a person receiving anthelmintics.

TABLE 13.2

DRUGS IN FOCUS Anthelmintics

Drug name

Dosage/route

Usual indications

albendazole (Eskazole, Zentel)

Hydatid disease: ≥60 kg: 400 mg b.d. PO

Treatment of active lesions caused by pork tapeworm and cystic disease of the liver, lungs and peritoneum caused by dog tapeworm

<60 kg: 15 mg/kg per day PO in divided doses, b.d., on a 28-day cycle, followed by 14 days of rest, for a total of three cycles Neurocysticercosis: ≥60 kg: 400 mg b.d. PO <60 kg: 15/mg/kg per day PO in divided doses, b.d., for 8–30 days of treatment

ivermectin (Stromectol)

150–200 mcg/kg PO as a single dose

Treatment of threadworm disease or strongyloidiasis; onchocerciasis or river blindness, which is found in tropical areas of Africa, Mexico and South America Treatment of diseases caused by pinworms, roundworms, whipworms and hookworms

100 mg PO morning and evening on three consecutive days Enterobiasis: 100 mg PO as a single dose Three doses of 20–25 mg/kg PO as a 1-day treatment 10 mg/kg PO as a single dose; maximum dose, 1 g

mebendazole (Ridworm, Vermox)

praziquantel (Biltricide)

Treatment of a wide number of schistosomes or flukes

pyrantel (Anthel, Combantrin)

Treatment of diseases caused by pinworms and roundworms; because administered in single dose, may be preferred for people who could have trouble remembering to take medication or following drug regimens

Drug therapy across the lifespan

BOX 13.2

Anthelmintic agents CHILDREN Culture of the suspected worm is important before beginning any drug therapy. The more toxic drugs—albendazole, ivermectin and praziquantel—should be avoided in children. The most commonly used anthelmintic, mebendazole, comes in a chewable tablet that is convenient for use in children. Nutritional status and hydration are major concerns with children taking these drugs who develop serious gastrointestinal effects. ADULTS Adults may be somewhat repulsed by the idea that they have a worm infestation, and they may be reluctant to

discuss the needed lifestyle adjustments and treatment plans. PREGNANCY AND BREASTFEEDING Pregnant and breastfeeding women should not use these drugs unless the benefit clearly outweighs the potential risk to the fetus or neonate. If a severe helminth infestation threatens the mother, some of the drugs can be used as long as the mother is informed of the potential risk. OLDER ADULTS Older people may be more susceptible to the central nervous system and gastrointestinal effects of some of these drugs. Dose adjustment is needed for these agents. Monitor hydration and nutritional status carefully.