What is the treatment for Giardiasis (Giardia intestinalis infection)?

From the Guidelines

Giardia infection should be treated with metronidazole, typically prescribed at 250 mg three times daily for 5-7 days for adults, as this regimen has been shown to be effective in eliminating the parasite and improving symptoms. The treatment of giardia is crucial to prevent prolonged diarrhea, malabsorption, and weight loss. According to a study published in 1, a single dose of 2 g of metronidazole can be used, however, this may not be the most effective regimen. Some key points to consider when treating giardia include:

• The importance of staying well-hydrated during treatment
• The potential need to temporarily avoid dairy products if experiencing lactose intolerance
• The side effects of metronidazole, which can include metallic taste, nausea, and the inability to be taken with alcohol
• The need for follow-up stool tests to confirm the parasites have been eliminated, especially in persistent cases
• The importance of prevention measures, such as proper handwashing and avoiding untreated water sources, to prevent reinfection. Alternative medications, such as tinidazole and nitazoxanide, may also be considered, but metronidazole remains the most commonly used treatment.

From the FDA Drug Label

1.2 Giardiasis Tinidazole is indicated for the treatment of giardiasis caused by Giardia duodenalis (also termed G. lamblia) in both adults and pediatric patients older than three years of age [see Clinical Studies ( 14.2)] . 14. 2 Giardiasis Tinidazole (2 g single dose) use in giardiasis has been documented in 19 published reports from the world literature involving over 1,600 patients (adults and pediatric patients) In eight controlled studies involving a total of 619 subjects of whom 299 were given the 2 g × 1 day (50 mg/kg × 1 day in pediatric patients) oral dose of tinidazole, reported cure rates ranged from 80% (40/50) to 100% (15/15).

The treatment for giardia is Tinidazole. The recommended dose is a single 2 g dose for adults, and 50 mg/kg for pediatric patients. Cure rates have been reported to range from 80% to 100% in clinical studies 2.

From the Research

Treatment Options for Giardia

• The first-line drug treatment for giardiasis is tinidazole, which requires only a single dose to cure infection in most individuals 3.
• Metronidazole is also effective, but it requires 5 to 7 days of three times a day therapy 3, 4.
• Nitazoxanide appears to be as effective as tinidazole or metronidazole, and it does not have the bitter taste of nitroimidazoles 3, 5.
• Paromomycin is a good alternate for use during pregnancy, as it is not systematically absorbed 3, 4.

Efficacy of Treatment Options

• A 5- to 7-day course of metronidazole can be expected to cure over 90% of individuals 4.
• A single dose of tinidazole or ornidazole will cure a similar number of individuals 4.
• Albendazole may be of similar effectiveness to metronidazole, and may have fewer side effects 6.
• Tinidazole was associated with higher parasitological cure than metronidazole and albendazole 7.

Side Effects and Contraindications

• Metronidazole can have gastrointestinal and neurological side effects 6.
• Albendazole probably has fewer side effects than metronidazole, including gastrointestinal and neurological side effects 6.
• Quinacrine may be poorly tolerated, especially in children 4.
• Furazolidone must be administered four times a day for 7 to 10 days, and may have side effects 4.