Key Points
- Treat visceral toxocariasis with antiparasitic drugs.
- Treatment of ocular toxocariasis usually consists of measures to prevent eye damage.
- Consider safety precautions of medications in different populations.
Overview
Treatment of visceral toxocariasis include the antiparasitic drugs albendazole or mebendazole. Treatment of ocular toxocariasis is more difficult and usually consists of measures to prevent progressive damage to the eye.
Optimal duration of albendazole or mebendazole treatment is undefined. Both drugs are metabolized in the liver; prolonged use of albendazole (weeks to months) has led to development of pancytopenia in some patients with compromised liver function.
Monitor patients on long-term treatment by serial blood cell counts. However, albendazole has been used to treat millions of patients worldwide and in mass drug administration campaigns, and it is considered a safe drug with low toxicity record. In addition to antiparasitic therapy, symptomatic therapy including steroid treatment to control inflammation may be indicated.
Drug
Dose and duration
Albendazole
400 mg by mouth twice a day for five days (both adult and pediatric dosage)
Mebendazole
100-200 mg by mouth twice a day for five days (both adult and pediatric dosage)
Oral albendazole and mebendazole are available for human use in the United States.
For ocular toxocariasis, the goal of treatment is to minimize damage to the eye. Systemic antiparasitic treatment with albendazole or mebendazole at the same doses as for visceral disease may be beneficial for active disease. Attempts to surgically remove the larva may be unsuccessful. Control of inflammation in the eye by use of topical or systemic steroids may be indicated. For patients with quiescent disease, improved outcomes may result from surgical intervention to prevent further damage due to chronic inflammation.
Care precautions
Treatment in Pregnancy
Albendazole is a pregnancy category C drug. There are limited data on the use of albendazole in pregnant women. The available evidence suggests no difference in congenital abnormalities in the children of women accidentally treated with albendazole during mass drug administration (MDA) campaigns compared with those who were not. In MDA campaigns for which the World Health Organization (WHO) has determined that the benefits of treatment outweigh the risks, WHO allows use of albendazole in the 2nd and 3rd trimesters of pregnancy. However, healthcare providers should balance the risks of treatment for the fetus with the risks of disease progression in the woman in the absence of treatment.
Pregnancy Category C: Either studies in animals have revealed adverse effects on the fetus (teratogenic or embryocidal, or other) plus there are no controlled studies in women, or studies in women and animals are not available. Prescribe albendazole only if the potential benefits to the woman justify the potential risks to the fetus.
Treatment during lactation
Albendazole is minimally excreted in human milk. WHO has concluded that a single oral dose of albendazole can be given to lactating women.
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 it is safe. According to WHO guidelines for MDA campaigns, children as young as one year of age (able to safely swallow tablets) can take albendazole. These campaigns have treated many children under six years old with albendazole, albeit at a reduced dose.
Treatment in Pregnancy
Mebendazole is a pregnancy category C drug. Data on the use of mebendazole in pregnant women are limited. The available evidence suggests no difference in congenital anomalies in the children of women treated with mebendazole during mass drug administration (MDA) campaigns compared with those who were not. In MDA campaigns in countries where soil-transmitted helminths are common, World Health Organization (WHO) has determined that the benefits of treatment outweigh the risks and WHO allows use of mebendazole in the 2nd and 3rd trimesters of pregnancy. However, in a pregnant woman infected with a soil-transmitted helminth, balance the risks of treatment for the fetus with the risks of disease progression in the woman in the absence of treatment.
Pregnancy Category C: Either studies in animals have revealed adverse effects on the fetus (teratogenic or embryocidal, or other) plus there are no controlled studies in women, or studies in women and animals are not available. Prescribe mebendazole only if the potential benefits to the woman justify the potential risks to the fetus.
Treatment during lactation
Mebendazole is minimally excreted in breast milk. WHO classifies mebendazole as compatible with breastfeeding and allows its use in lactating women.
Treatment in pediatric patients
The safety of mebendazole in children is unclear. There are limited data in children under 2 years old. The WHO Model List of Essential Medicines for Children lists mebendazole as an intestinal antihelminthic medicine that can be used for children older than 2 years of age.