Learning objectiveyou should be able to:

• List the major group of antiamebiasis

• Choose the drug for asymptomatic, andsymptomatic amebiasis

• Identify the drugs useful in amebic liverabscess

• Identify side effects of antiamebiasis

• List the clinical aplication of metronidazole

 

case

•  A female patient complain lower abdominaldiscomfort, flatulence, diarrhea. Patient isdiagnosed as symptomatic amebiasis.E.histolytica  is identified in her stool. The doctorprescribe an oral drug, which reduces herintestinal symptom. Later she got a severedysentry, fever, weight loss and enlarge liver.Diagnosis now, amebic liver abscess. She has ahistory of disrrythmia.How do you manage this patient ?

 

 Amebiasis occurs in two forms• Bowel lumen amebiasis/asymptomatic amebiasis

treated by lumen amebicides:

diloxanide furoate

iodoquinol

tetracycline

paromomycin

• Tissue invading amebiasis/symptomatic dysentery &hepatic amebiasis, treated by tissue amebicides:

metronidazole

emetine & dihydroemetine

chloroquine

always combined with luminal amebicides

 

Diloxanide Furoate

• Useful in eradicating the bowel lumen dwellingform

• 90% is rapidly absorbed and conyugated to formthe glucuronide, promptly excreted in the urine

• Converted in the gut to diloxanide freebase

• The commonest adverse effect is flatulence

 

Iodoquinol

• Diiodohydroxyquinoline & clioquinol

• 90% retained in the intestine

• Less effective than diloxanide

• Adverse effect:

g.i.symptom

thyroid enlargement

neurotoxic effect (SMON)

 

Tetracycline

• Indirectly amebicide by modifying theintestinal flora which necessary for amebato survive

 

Paromomycine

• Aminoglycoside antibiotic

• Direct amebicidal action

 

Chloroquine

• Effective only in hepatic amebiasis (highconcentration in liver)

• Less effective than emetine

• Should be given in combination withemetine or metronidazole

 

Emetine & dihydroemetine

• Equally effective with metronidazole

• But more toxic

• Administered parenterally, accumulate intissue, eliminated slowly via kidney

• Toxic to the myocardium (arrhythmia andcongestive heart failure)

• Should not be used in patient cardiac orrenal disease, elderly, young children,pregnancy

 

Metronidazole

• Has potent amebicidal activity

• Orally active

• Eradicate tissue infection

• The drug of first choice in tissue amebiasis

• Adverse effects:

g.i tract irritation

disulfiram like reaction (with alcohol)

coumarin effect increase

dark coloration of urine

 

Summary

• Two major group of antiamebiasis: luminalamebicides, tissue amebicides

• For asymptomatis: diloxanide furoate

• For symptomatis: metronidazole

• Drugs useful in amebic liver abscess:metronidazole, emetin, chloroquine. Should befollowed by lumen amebicide

• Clinical aplication of Metronidazole: intestinaland extraintestinal wall amebiasis, trichomonas,giardiasis, anaerobic bacteria