• Drugs used to treat amebiasis categories

  • Tissue amebicides:

    • Nitroimidazoles:

      •  Metronidazole (Flagyl)

        • Very effective in bowel wall and other tissues

        • Partially effective and NOT adequate as luminal amebicides {metronidazole (Flagyl) alone may fail to cure as much as 50% of intestinal disease}

    • Emetines:

      •  Emetine (generic) and dehydroemetine (Mebadin)

      •  Intramuscular injection-act on bowel-wall/tissue organisms; NOT on luminal amebas

    • Chloroquine (Aralen)-primary activity against hepatic amebas

  • Luminal amebicides (active in bowel lumen-not effective against amebas in bowel wall/other tissues)

    •  Dichloroacetamides

      • Diloxanide furoate (Furamide)

      • Others available outside USA-clefamide, teclozan, etofamide

    •  Halogenated hydroxyquinolines

      • Iodoquinol (Yodoxin, Moebequin)

      • Available outside the USA-clioquinol

  • Antibiotics

    •  Paromomycin (Humatin) and erythromycin: directly amebicidal

    •  Oral tetracyclines inhibit bacterial associates of bowel luminal E. histolytica-as a result affect luminal amebas

    •  Paromomycin (Humatin)-highly effective; other antibiotics should not be used as monotherapy because of their limited effectiveness.

  • Drug Treatment of Asymptomatic Intestinal Infection:

    • Management in endemic areas: asymptomatic carriers not treated due to high-risk of reinfection

    • Management in nonendemic regions:

      • Treat asymptomatic carriers with a luminal amebicide:

        •  Drugs of choice-cure frequency: 80%-90% using a single treatment course

          • Diloxanide furoate (Furamide)-fewer side effects

          • Iodoquinol (Yodoxin, Moebequin)

        • Alternative agents (treatment/re-treatment)

          • Paromomycin (Humatin)

          • Metronidazole (Flagyl) + iodoquinol (Yodoxin, Moebequin) or diloxanide.

• Drug Treatment of Mild-Moderate Intestinal Infection

  • Treatment of choice: Metronidazole (Flagyl) + a luminal amebicide

  • Some alternative treatments available --

• Drug Treatment of Severe Intestinal Amebiasis

  • Drugs of choice include metronidazole (Flagyl) plus diloxanide furoate (Furamide) or iodoquinol (Yodoxin, Moebequin);

    • If parenteral administration is initially required, use intravenous metronidazole (Flagyl) then oral treatment when possible

  • Alternative drugs include:

    • A tetracycline + diloxanide furoate (Furamide) or iodoquinol (Yodoxin, Moebequin), followed by chloroquine (Aralen)

    • If parenteral treatment is initially required:

      • Dehydroemetine (Mebadin) or emetine (generic), followed by

        • A tetracycline + diloxanide furoate (Furamide) or iodoquinol (Yodoxin, Moebequin) followed by

        • Chloroquine (Aralen)

• Hepatic Abscess

  • Nonpharmacological: bed rest/hospitalization

  • Ultrasound Radiological Study of amebic liver abscess:

    • courtesy of:  Department of Radiology, Brigham and Women's Hospital, Harvard Medical School

  •  Drug treatments of choice:

    •  Metronidazole (Flagyl)-ten day protocol/cure rate: > 95% its (uncomplicated cases)

      •  For treatment failure: follow metronidazole (Flagyl) protocol with chloroquine (Aralen)

      •  Additional advantage of metronidazole (Flagyl): effective against bacterial liver abscess, as well -- due to anaerobic bacteria

    • Also required: luminal amebicide {independent of positive stools}

      •  Diloxanide furoate (Furamide)

      •  Iodoquinol (Yodoxin, Moebequin)

  • Potentially more toxic alternative drugs:

    •  Dehydroemetine (Mebadin)

    •  Emetine (generic)

• Ameboma/Extraintestinal amebiasis

  • Drug or choice: metronidazole (Flagyl)

  • Alternative drugs: dehydroemetine (Mebadin) oremetine (generic)

  • Not acceptable: chloroquine (Aralen)-insufficient tissue concentration (except hepatic) to be effective

  • Concurrent luminal amebicide also required.

Primary Reference: Goldsmith, R. S., Antiprotozoal Drugs in Basic and Clinical Pharmacology (Katzung, B. G., ed) Appleton-Lange, 1998, p. 838-861.

Primary Reference: Morgan, Juliette and del Rio, Carlos, Amebiasis in Medicine for the Practicing Physician (Hurst, J. W., ed) Appleton-Lange, 1996, pp. 457-459.