Key points
- Ivermectin and albendazole can treat Strongyloides infections.
- In severe cases, immunosuppressive therapy should be reduced or stopped if possible.
- In patients with positive stool examination for Strongyloides and persistent symptoms conduct follow-up exams 2 – 4 weeks after treatment.
Treatment recommendations
Two drugs are available in the United States to treat acute and chronic strongyloidiasis.
First-line therapy
Drug
Dosage
Relative contraindications
Ivermectin
Single dose, 200 µg/kg orally for 1 – 2 days
- Confirmed or suspected concomitant Loa loa infection
- Persons weighing less than 15kg
- Pregnant or lactating women
Alternative
Drug
Dosage
Relative contraindications
Albendazole
400 mg orally two times a day for 7 days
- Hypersensitivity to benzimidazole compounds or any component of product
- Use should be avoided in the 1st trimester of pregnancy
Both oral ivermectin and oral albendazole is available for human use in the United States.
In patients with positive stool examination for Strongyloides and persistent symptoms, follow-up stool exams should be performed 2 – 4 weeks after treatment to confirm clearance of infection. If recrudescence of larvae is observed, retreatment is indicated.
Hyperinfection syndrome/Disseminated strongyloidiasis
If possible, immunosuppressive therapy should be stopped or reduced, and:
Drug
Dosage
Ivermectin
200 µg/kg per day orally, until stool and/or sputum exams are negative for 2 weeks
For patients unable to tolerate oral therapy, such as those with ileus, obstruction, or known or suspected malabsorption, published case reports have demonstrated efficacy with rectal administration.
If oral and/or rectal administrations are not possible, there have been instances where Investigational New Drug (IND) exemptions for the veterinary subcutaneous formulation of ivermectin have been granted by the FDA.
Screening
Healthcare providers should be particularly diligent to consider Strongyloides in patients:
- Who are on or about to begin corticosteroid therapy or other immunosuppressants
- Known to have HTLV-1 infection
- With hematologic malignancies including leukemias and lymphomas
- Who have had or are being considered for organ transplantation
- With persistent peripheral or unexplained eosinophilia
- With recent or remote travel histories to endemic areas.
Of note, although persons with HIV can have disseminated strongyloidiasis or hyperinfection syndrome, observational studies have not shown an increased risk in this population.
Care Precautions
Standard precautions should be observed for patients hospitalized with strongyloidiasis. Wearing gloves and gowns, good hygiene, and diligent handwashing is important when coming into contact with the patient's feces.
Note on Treatment in Pregnancy
Albendazole is pregnancy category C. Data on the use of albendazole in pregnant women are limited, though the available evidence suggests no difference in congenital abnormalities in the children of women who were accidentally treated with albendazole during mass prevention campaigns compared with those who were not. In mass prevention campaigns for which the World Health Organization (WHO) has determined that the benefit of treatment outweighs the risk, WHO allows use of albendazole in the 2nd and 3rd trimesters of pregnancy. However, the risk of treatment in pregnant women who are known to have an infection needs to be balanced with the risk of disease progression in the absence of treatment.
Pregnancy Category C: Either studies in animals have revealed adverse effects on the fetus (teratogenic or embryocidal, or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the fetus.
Note on Treatment During Lactation
It is not known whether albendazole is excreted in human milk. Albendazole should be used with caution in breastfeeding women.
Note on Treatment in Pediatric Patients
The safety of albendazole in children less than 6 years old is not certain. Studies of the use of albendazole in children as young as one year old suggest that its use is safe. According to WHO guidelines for mass prevention campaigns, albendazole can be used in children as young as 1 year old. Many children less than 6 years old have been treated in these campaigns with albendazole, albeit at a reduced dose.
Note on Treatment in Pregnancy
Ivermectin is pregnancy category C. Data on the use of ivermectin in pregnant women are limited, though the available evidence suggests no difference in congenital abnormalities in the children of women who were accidentally treated during mass prevention campaigns with ivermectin compared with those who were not. The World Health Organization (WHO) excludes pregnant women from mass prevention campaigns that use ivermectin. However, the risk of treatment in pregnant women who are known to have an infection needs to be balanced with the risk of disease progre ssion in the absence of treatment.
Pregnancy Category C: Either studies in animals have revealed adverse effects on the fetus (teratogenic or embryocidal, or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the fetus.
Note on Treatment during Lactation
Ivermectin is excreted in low concentrations in human milk. Ivermectin should be used in breast-feeding women only when the risk to the infant is outweighed by the risk of disease progress in the mother in the absence of treatment.
Note on Treatment in Pediatric Patients
The safety of ivermectin in children who weigh less than 15kg has not been demonstrated. According to the WHO guidelines for mass prevention campaigns, children who are at least 90 cm tall can be treated safely with ivermectin. The WHO growth standard curves show that this height is reached by 50% of boys by the time they are 28 months old and by 50% of girls by the time they are 30 months old, many children less than 3 years old been safely treated with ivermectin in mass prevention campaigns, albeit at a reduced dose.