Antiamebic drugs

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Antiamebic drugs
Pawitra Pulbutr M. Sc. In Pharm (Pharmacology)
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Amebiasis
Entamoeba histolytica infection .... Protozoa
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Forms of Amebiasis
1. Asymptomatic intestinal infection 2. Mild to
moderate intestinal infection 3. Severe
intestinal infection (dysentery) 4. Hepatic
abscess 5. Ameboma or extrahepatic forms of
amebiasis
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Antiamebic drugs
Kill... trophozoite

• Tissue Amebicides
• Active at intestinal wall, liver, other tissues
• Not effective in lumen
• Nitroimidazole
• Metronidazole, Tinidazole, Nimorazole,
  Ornidazole
• Emetines
• Chloroquine...Liver

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Antiamebic drugs

• Luminal amebicides
• Active in intestinal lumen
• Dichloroacetamides
• Diloxanides furoate
• Halogenated hydroxyquinolines
• iodoquinol
• clioquinol
• Antibiotics Paromomycin, Tetracyclines,
  Erythromycin

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Metronidazole

• Tissue amebicides
• Most effective for invasive amebiasis
• Expected mechanism...
• Toxic oxygen products
• Destroy trophozoite DNA

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Metronidazole
Clinical uses

• Drug of choice for
• intestinal amebiasis
• extraintestinal amebiasis
• congenital trichomiasis

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• Other Nitroimidazole
• Tinidazole
• Nimorazole
• Ornidazole
• Longer half life

Metronidazole Flagyl Tinidazole Fasigyn
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Emetine Dehydroemetine

• tissue amebicide
• Irreversible block of protein synthesis
• Block ribosome translocation on mRNA
• Parenterally
• Accumulate in liver, lung, spleen, kidney

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Chloroquine

• High level in liver
• use in ...
• Amebic liver abscess...ONLY

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Luminal amebicides
Diloxanide furoate

• direct amebicideunknown mechanism
• dissociate in lumen into diloxanide furoic
  acid
• 90 diloxanide absorption
• Unabsorbed diloxanide....Active luminal amebicide

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Iodoquinol

• iodoquinol diiodohydroxyquin
• luminal amebicide
• Unknown mechanism of action
• Interfere thyroid function test
• decrease 131I uptake
• Alternative to diloxanide furoate

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Treatment amebiasis
Asymptomatic intestinal infection

• not necessary in endemic area... Reinfection
• Luminal amebicide
• DOC....diloxanide furoate

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Treatment amebiasis

• Mild to moderate intestinal infection
• Severe intestinal infection (dysentery)
• Hepatic abscess / other extrahepatic infection

Tissue amebicide Luminal amebicide

• DOC
• Metronidazole diloxanide furoate

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THE END