eMedicine Specialties > Pediatrics: General Medicine > Parasitology
Ancylostoma Infection: Treatment & Medication
Updated: May 1, 2008
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
- Multimedia
Treatment
Medical Care
- Classic hookworm disease
- Most cases of classic hookworm disease can be managed on an outpatient basis with anthelminthic and iron therapy, complemented by appropriate diet.
- Some patients with severe anemia and congestive heart failure may require hospitalization.
- Blood transfusion is indicated in rare cases of acute severe GI hemorrhage. In patients with chronic anemia, blood transfusions (ie, packed RBCs) should be administered slowly and are usually followed by a diuretic to prevent rapid fluid overload.
- Cutaneous larva migrans: Specific anthelminthic treatment may be unnecessary for patients with cutaneous larva migrans who have minimal symptoms.
Surgical Care
Eosinophilic enteritis may mimic acute appendicitis or intestinal perforation, and, in some cases, diagnosis has been made during laparotomy. However, treatment for eosinophilic enteritis is medical (ie, mebendazole administration) rather than surgical.
Consultations
Consultations are usually unnecessary unless the anemia is severe or blood indices are equivocal.
Diet
The diet for patents with ancylostoma infection should be rich in iron and protein.
Medication
The treatment of classic hookworm infection has 2 components: (1) correcting the anemia, which is usually achieved by means of iron therapy and proper diet, and (2) expelling the intestinal parasites. In rare cases (eg, acute severe GI hemorrhage), blood transfusion may be needed to correct anemia.
Anthelminthic drugs effective against hookworms include pyrantel pamoate, benzimidazoles (eg, albendazole, mebendazole, thiabendazole), and ivermectin.5,6 A single 400-mg dose of albendazole is the treatment of choice.7 Mebendazole 100 mg twice daily for 3 days is more effective than a single 500-mg dose. Several 11 mg/kg doses of pyrantel pamoate may be require for cure.
Anthelminthics
Most helminths, including hookworms, cannot replicate within a human host. Chemotherapy reduces the number of adult worms unless reinfection occurs.
Parasite biochemical pathways are different from those in human hosts; thus, toxicity is directed to the parasite, egg, or larvae. Mechanism of action varies within the drug class. Antiparasitic actions may include the following:
- Inhibition of microtubules causes irreversible block of glucose uptake
- Tubulin polymerization inhibition
- Depolarizing neuromuscular blockade
- Cholinesterase inhibition
- Increased cell membrane permeability, resulting in intracellular calcium loss
- Vacuolization of the schistosome tegument
- Increased cell membrane permeability to chloride ions via chloride channels alteration
Because of the relative toxicity of thiabendazole, systemic administration is not recommended for GI nematode infections; safer alternatives are available. In children younger than 2 years, in whom experience with antihelminthics is limited, the World Health Organization (WHO) recommends administering half the adult dose of albendazole or mebendazole for patients with heavy hookworm infections. Pyrantel dosages are determined by patient weight. For pregnant women with heavy hookworm infections, the WHO recommends deworming treatment during the second or third trimester using albendazole, mebendazole, or pyrantel.
Albendazole (Albenza)
FDA-approved but considered investigational to treat hookworms; inhibits microtubule polymerization by binding to cytoplasmic b -tubulin; by affecting intestinal cells of parasite, prevents use of nutrients by parasite, essentially starving it to death.
Dosage shown is selectively toxic to parasites because binding to parasite b -tubulin occurs at a much lower concentration than binding to mammalian protein.
Because drug acts locally on worms within GI tract, action is not dictated by systemic drug concentration.
In children, albendazole appears superior to mebendazole for curing hookworm infestations (cure rates of approximately 90% for Ancylostoma and 75% for Necator using albendazole).
Adult
For classic hookworm disease and eosinophilic enteritis: 400 mg PO once
For cutaneous larva migrans: 400 mg PO qd for 3 d
Pediatric
<6 years: Not established
>6 years: Administer as in adults
Coadministration with carbamazepine may decrease efficacy; dexamethasone, cimetidine, and praziquantel may increase toxicity
Documented hypersensitivity
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Information based on use to treat patients with hydatid disease and neurocysticercosis, for which the drug is used for prolonged periods (8-30 d for neurocysticercosis and 3 mo for hydatid disease); embryotoxic and teratogenic in pregnant rats and rabbits; no adequate studies in pregnant women, but no deleterious effects were recorded among 10 cases of women who were exposed accidentally to high doses of albendazole for systemic infection during first trimester and followed to term; excreted in animal milk; whether excreted in human milk unknown
Patients with abnormal liver function test (LFT) findings should be carefully evaluated before commencing therapy because drug metabolized in liver and associated with hepatotoxicity; most common adverse effect is reversible increase in serum aminotransferases (16%); abdominal pain, diarrhea, nausea, dizziness, and headache occasionally occur (just above 1%); causes reversible reductions in total WBC count in <1% of patients
Mebendazole (Vermox)
Recommended for treatment of eosinophilic enteritis; inhibits microtubule polymerization by binding to cytoplasmic b -tubulin; by affecting parasite's intestinal cells, prevents use of nutrients and essentially starves parasite to death; dosage shown is selectively toxic to parasites because binding to parasite b -tubulin occurs at much lower concentration than binding to mammalian protein; because drug acts locally on worms within GI tract, action not dictated by systemic drug concentration.
A repeat stool examination using a concentration technique is recommended after 2 wk, and retreatment is indicated if results are positive. No fasting or purging is required. Tab may be chewed, swallowed, or crushed and mixed with food.
Adult
100 mg PO bid for 3 d or 500 mg PO once (some studies show better cure rates using multidose regimen)
Pediatric
<2 years: Not established
>2 years: Administer as in adults
Carbamazepine and phenytoin may decrease effects; cimetidine may increase levels
Documented hypersensitivity
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Found to be embryotoxic and teratogenic in pregnant rats at single PO doses as low as 10 mg/kg (approximately equal to the human dose, based on mg/m2); on the basis of these findings, not recommended in pregnant women, especially in first trimester; no adequate studies of administration in pregnant women, although postmarketing studies in 170 pregnant women who had inadvertently taken the drug did not reveal higher than usual incidence of spontaneous abortions or malformations; not known whether mebendazole is excreted in human milk; therapy may not eradicate dormant larvae residing in extraintestinal tissues because drug is poorly absorbed into systemic circulation
Abdominal pain and diarrhea may occur in massive infections and expulsion of GI worms; rare reports of neutropenia and agranulocytosis when used for prolonged periods and at higher than recommended doses; elevated liver enzymes and, rarely, hepatitis occur when mebendazole used for prolonged periods and administered in dosages substantially above those recommended
Pyrantel pamoate (Antiminth)
FDA-approved but considered investigational for this condition; depolarizing neuromuscular blocking agent that inhibits cholinesterases, resulting in spastic paralysis of the worm.
Adult
11 mg/kg (5 mg/lb) PO for 3 d, not to exceed 1 g, without regard to ingestion of food or time of day
Pediatric
<2 years: Not established
>2 years: Administer as in adults
In ascariasis, pyrantel and piperazine are mutually antagonistic and should not be used concomitantly; theophylline serum levels may increase in pediatric patients, following pyrantel pamoate administration
Documented hypersensitivity; hepatic disease
Pregnancy
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Precautions
Caution in liver impairment, anemia, and malnutrition; transient GI symptoms, headache, and dizziness occasionally observed
Thiabendazole (Mintezol)
FDA-approved but considered investigational for this condition; indicated only for cutaneous larva migrans; inhibits microtubule polymerization by binding to cytoplasmic β -tubulin; by affecting intestinal cells of parasite, prevents use of nutrients, essentially starving parasite to death.
Dosage shown is selectively toxic to parasites because binding to parasite β -tubulin occurs at a much lower concentration than binding to mammalian protein.
Administer PO dose pc; tabs should be chewed before swallowing.
Adult
Topical administration (for cutaneous larva migrans): Apply 10-15% susp to lesions 4-6 times daily for 2-5 d
PO: 25 mg/kg/dose bid for 2-5 d; not to exceed 1.5 g/dose
Pediatric
<30 lb: Not established
>30 lb: Administer as in adults
May elevate serum levels of theophylline, increasing toxicity (monitor serum levels and reduce dose prn)
Documented hypersensitivity
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Closely monitor in hepatic or renal dysfunction; before initiating therapy, supportive therapy necessary for anemic, dehydrated, or malnourished patients; use in confirmed worm infestation, not prophylactically; may cause nausea, vomiting, and mild CNS depression; associated with erythema multiforme, including Stevens-Johnson syndrome; animal studies reveal no teratogenic effects; no adequate studies in pregnant women; whether excreted in human milk unknown; potentially serious adverse reactions in infants requires decision whether to discontinue breastfeeding or thiabendazole
Ivermectin (Stromectol, Mectizan)
FDA-approved but considered investigational for this condition; recommended for treatment of cutaneous larva migrans; binds selectively with glutamate-gated chloride ion channels in invertebrate nerve and muscle cells, causing cell death.
Adult
200 mcg/kg/d PO for 1-2 d
Pediatric
<5 years: Not established
>5 years: Administer as in adults
May interact with other ligand-gated chloride channels (eg, those gated by GABA)
Documented hypersensitivity
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Treat mothers who intend to breastfeed only when risk of delayed treatment outweighs possible risks to newborn caused by ivermectin excretion in milk; repeat courses of therapy may be required in patients who are immunocompromised; may cause drowsiness, nausea, vomiting, and mild CNS depression
More on Ancylostoma Infection |
| Overview: Ancylostoma Infection |
| Differential Diagnoses & Workup: Ancylostoma Infection |
 Treatment & Medication: Ancylostoma Infection |
| Follow-up: Ancylostoma Infection |
| Multimedia: Ancylostoma Infection |
| References |
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References
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Further Reading
Keywords
hookworm infection, hookworm, hookworm disease, Ancylostomatidae, Ancylostoma duodenale, Necator americanus, Ancylostoma caninum, Ancylostoma ceylanicum, Ancylostoma braziliense, cutaneous larva migrans, eosinophilic enteritis, iron deficiency anemia, protein malnutrition, iron deficiency anemia, protein malnutrition, helminthic infections, hookworm anemia, malabsorption, hypoproteinemia, malnutrition, GI hemorrhage, ancylostoma infection, ground itch, dew itch, Wakana disease, melena, leukocytosis, erythema
