Intestinal Protozoal Diseases Medication

Updated: Apr 26, 2017
  • Author: Enrique Chacon-Cruz, MD; Chief Editor: Russell W Steele, MD  more...
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Medication

Medication Summary

The drugs of choice for each protozoon are listed in Table 3 and are followed by specific considerations for each drug.

Table 3. Specific Therapy for Intestinal Protozoal Infections (Open Table in a new window)

Organism

Drugs, Pediatric Dose, and Treatment Duration

E histolytica (Luminal disease or colonization)

Iodoquinol: 40 mg/kg/d PO divided tid for 20 d; not to exceed 2 g/d

Paromomycin: 25-30 mg/kg/d PO divided tid for 7 d

E histolytica (Moderate colitis)

Metronidazole: 50 mg/kg/d PO divided tid for 10 d

Tinidazole: 50 mg/kg/d PO for 3 d; not to exceed 2 g/d

E histolytica (Severe colitis or liver abscess)

Metronidazole: 50 mg/kg/d PO divided tid for 10 d

Dehydroemetine*: 1-1.5 mg/kg/d divided bid PO for 5 d

Tinidazole†: 50 mg/kg/d PO for 3-5 d; not to exceed 2 g/d

G lamblia

Tinidazole: 50 mg/kg/d PO once; not to exceed 2 g/dose

Metronidazole: 15-20 mg/kg/d PO divided tid for 5

Albendazole: 15 mg/k/d (not exceed 400 mg) PO q24 h, for 5-7 days

Furazolidone: 6 mg/kg/d PO divided qid for 7-10 d

Paromomycin: 40 mg/kg/d PO divided tid for 7 d

Nitazoxanide: 200-400 mg/d PO divided bid for 3 d

D fragilis

Iodoquinol: 50 mg/kg/d PO divided tid for 20 d; not to exceed 2 g/d

Paromomycin: 30 mg/kg/d PO divided tid for 7 d

Tetracycline: 40 mg/kg/d PO divided qid for 10 d; not to exceed 2 g/d

C parvum§

Paromomycin*: 30 mg/kg/d PO divided tid (duration unknown)

Nitazoxanide: 200-400 mg/d PO divided bid for 3 d

I belli

Trimethoprim/sulfamethoxazole (TMP/SMZ): 20/100 mg/kg/d PO divided bid for 10 d, followed by 10/50 mg/kg/d PO divided bid for 21 d

C cayetanensis

TMP/SMZ: 10/50 mg/kg/d PO divided bid for 3 d

Microsporidia S intestinalis

Albendazole* (adult dose): 800 mg/d PO divided bid

Microsporidia E bieneusi

No treatment recommended; albendazole may decrease the number of organisms

B coli

Tetracycline: 40 mg/kg/d PO divided qid for 10 d; not to exceed 2 g/d

Metronidazole: 35-50 mg/kg/d PO divided tid for 5 d

Iodoquinol: 40 mg/kg/d PO divided tid for 20 d

B hominis

Metronidazole: 35-50 mg/kg/d PO divided tid for 10 d

Iodoquinol: 40 mg/kg/d PO divided tid for 20 d

Nitazoxanide||: 500 mg/d PO divided bid for 3 d

*Efficacy is unknown.

†Drug is available from the CDC Drug Service (phone: 404-639-3670; evenings, weekends, and holidays: 404-639-2888).

‡ Drug is not available in the United States.

§Recommended regimens are indicated only in patients who are immunosuppressed. A recent meta-analysis has not shown evidence for a reduction in the duration or frequency of diarrhea by nitazoxanide or paromomycin when compared with placebo in immunosuppressed patients, nevertheless, oocyst clearance was significantly reduced. [23]

||Recent studies have shown effective outcomes when compared to placebo, but no clinical trials have compared with other antiparasitic drugs.

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Antiprotozoal agents

Class Summary

Protozoal infections occur throughout the world and are a major cause of morbidity and mortality in some regions. Immunocompromised patients are especially at risk. Primary immune deficiency is rare, whereas secondary deficiency is more common. Immunosuppressive therapy, cancer and its treatment, HIV infection, and splenectomy can all increase vulnerability to infection. Infectious risk is proportional to neutropenia duration and severity. Protozoal infections are typically more severe in immunocompromised patients than in immunocompetent patients. In the case of cryptosporidiosis, nitazoxanide has been shown to be effective in immunocompetent and probably in immunocompromised patients, and the role of HAART has significantly reduced the incidence of all spore-forming protozoal infections.

Iodoquinol (Yodoxin)

Used for infections caused by E histolytica, B coli, B hominis, and D fragilis. Iodoquinol, also known as diiodohydroxyquin, is a halogenated quinoline.

Metronidazole (Flagyl)

Used for infections caused by E histolytica, B coli, B hominis, and G lamblia. Metronidazole is a nitroimidazole.

Paromomycin (Humatin)

Used for infections caused by E histolytica, G lamblia, D fragilis, and C parvum. It is a nonabsorbable oral aminoglycoside.

Tetracycline (Sumycin)

Used for infections caused by B coli and D fragilis. It is a broad-spectrum antibiotic.

Trimethoprim/sulfamethoxazole (TMP/SMZ, Bactrim, Septra)

Used for infections caused by C cayetanensis and I belli. It is a broad-spectrum antibacterial and antiprotozoal antibiotic. Considered DOC for isosporiasis and cyclosporiasis.

Dehydroemetine (Mebadin)

Not FDA-approved in the United States. Used for infections caused by E histolytica. It is a main alkaloid of ipecac, less toxic than emetine; used only in combination with other drugs against severe forms of invasive amebiasis. Available in US only from the Parasitic Disease Drug Service, CDC (Atlanta, GA 30333; telephone: 404-639-3670). For more information, see CDC Drug Service.

Furazolidone (Furoxone)

Used for infections caused by G lamblia; it is an oxazolidine and belongs to the group of the nitrofurans.

Quinacrine (Atabrine)

Used for infections caused by G lamblia. It is an acridine derivative.

Albendazole (Albenza)

Used for infections caused by E bieneusi. It is an imidazole derivative, mostly used for helminths. Its efficacy against microsporidia is still unknown.

Tinidazole (Fasigyn, Tindamax)

Nitroimidazole, similar to metronidazole. It is used for infections caused by E histolytica and G lamblia.

Nitazoxanide (Alinia)

Inhibits growth of C parvum sporozoites and oocysts and G lamblia trophozoites. Elicits antiprotozoal activity by interfering with pyruvate-ferredoxin oxidoreductase (PFOR) enzyme-dependent electron transfer reaction, which is essential to anaerobic energy metabolism. Available as a 20-mg/mL oral susp.

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