What is the treatment for Gastrointestinal (GI) intestinal parasites?

From the Guidelines

Treatment for gastrointestinal intestinal parasites typically involves antiparasitic medications specific to the type of parasite identified, with albendazole and mebendazole being effective first-line treatments for common intestinal worms like roundworms, pinworms, and hookworms, as recommended by the most recent guidelines 1. For common intestinal worms, medications such as albendazole (400mg as a single dose for most adults) or mebendazole (100mg twice daily for 3 days) are effective first-line treatments.

• For giardiasis, metronidazole (250mg three times daily for 5-7 days) or tinidazole (2g single dose) are recommended 1.
• Amoebiasis is typically treated with metronidazole (750mg three times daily for 5-10 days) followed by paromomycin (25-35mg/kg/day in three doses for 7 days) to eliminate cysts. During treatment, maintaining good hydration is essential, and some patients may need supportive care for symptoms like diarrhea.
• Proper hygiene practices including thorough handwashing, avoiding contaminated food and water, and proper food preparation are crucial to prevent reinfection. Treatment effectiveness should be confirmed with follow-up stool examinations, and family members or close contacts may need treatment simultaneously to prevent reinfection cycles, especially with highly contagious parasites like pinworms. In cases of microsporidia infection, albendazole (dosage for person weighing <60 kg is 7.5 mg/kg orally twice daily; maximum dose: 400 mg orally twice daily) decreases diarrhea, sometimes with eradication of the organism, as noted in earlier guidelines 1, but more recent guidelines provide a broader range of treatment options for various parasites 1.

From the FDA Drug Label

Ivermectin is active against various life-cycle stages of many but not all nematodes. It is active against the tissue microfilariae of Onchocerca volvulus but not against the adult form. Its activity against Strongyloides stercoralis is limited to the intestinal stages

Clinical Studies Strongyloidiasis Two controlled clinical studies using albendazole as the comparative agent were carried out in international sites where albendazole is approved for the treatment of strongyloidiasis of the gastrointestinal tract, and three controlled studies were carried out in the U. S. and internationally using thiabendazole as the comparative agent.

Efficacy, as measured by cure rate, was defined as the absence of larvae in at least two follow-up stool examinations 3 to 4 weeks post-therapy.

Based on this criterion, efficacy was significantly greater for STROMECTOL (a single dose of 170 to 200 mcg/kg) than for albendazole (200 mg b.i. d. for 3 days).

Treatment for GI intestinal parasite:

• Ivermectin is effective against the intestinal stages of Strongyloides stercoralis.
• The recommended dose is a single dose of 170 to 200 mcg/kg.
• Cure rate is defined as the absence of larvae in at least two follow-up stool examinations 3 to 4 weeks post-therapy.
• Efficacy was significantly greater for ivermectin than for albendazole in clinical studies 2

From the Research

Treatment Options for GI Intestinal Parasites

The treatment for GI intestinal parasites depends on the type of parasite and the severity of the infection. Some common treatment options include:

• Metronidazole: effective against giardiasis, amoebiasis, and other intestinal protozoa 3, 4, 5, 6
• Albendazole: effective against hookworm, Ascaris lumbricoides, pinworm, and other intestinal helminths 4, 7, 6
• Tinidazole: effective against giardiasis and other intestinal protozoa, with higher parasitological cure rates than metronidazole 5, 6
• Nitazoxanide: effective against cryptosporidiosis and other intestinal protozoa 3, 6
• Ivermectin: effective against Strongyloides stercoralis and other intestinal helminths 7
• Praziquantel: effective against intestinal trematode infections and tapeworms 7

Considerations for Treatment

When choosing a treatment option, considerations should include:

• The type and severity of the infection
• The patient's age, health status, and immune function
• The potential side effects and interactions of the treatment
• The availability and cost of the treatment
• The need for combination therapy or multidrug regimens in certain cases 3, 7

Efficacy of Treatment Options

Studies have compared the efficacy of different treatment options for GI intestinal parasites, including:

• Metronidazole vs. albendazole for giardiasis: albendazole may be equivalent to metronidazole in achieving parasitological cure, but with fewer side effects 6
• Tinidazole vs. metronidazole for giardiasis: tinidazole may have higher parasitological cure rates than metronidazole 5
• Albendazole vs. ivermectin for hookworm and other intestinal helminths: albendazole may be more effective than ivermectin in certain cases 7