Amoebiasis and Amoebicides Flashcards
What is the causative agent of amoebiasis?
Entamoeba histolytica
How is amoebiasis transmitted?
Through the ingestion of food/water contaminated with the faecal matter of infected individual containing E. histolytica cysts.
Mention 5 symptoms of amoebiasis.
- Diarrhoea
- Abdominal pain
- Dysentery
- Fatigue
- Loss of appetite
Describe mild amoebiasis.
- No symptoms, but E. histolytica is present in guts
- No intestinal or blood invasion
- No complications
Describe severe amoebiasis.
- Intestinal invasion: causes bleeding (amoebic dysentery)
- Blood invasion: causes liver abscess, colonic perforation, severe colitis
Mention 3 complications of amoebiasis.
- Colonic perforation
- Anaemia
- Severe colitis
How do you prevent amoebiasis?
- Wash hands after toilet use
- Frequently clean bathroom and toilet
- Avoid sharing towels
- Avoid raw vegetables in endemic areas
- Boil or treat water with iodine tablets before drinking
- Avoid eating street food
Classify amoebicides.
A. Tissue amoebicides: destroy E. histolytica in tissues
i. Nitroimidazoles
ii. Isoquinolones
B. Luminal amoebicides: destroy E. histolytica in the lumen
i. Hydroxyquinoline
ii. Dichloroacetamide
iii. Aminoglycosides
List 5 nitroimidazoles using in treating amoebiasis.
- Metronidazole
- Ornidazole
- Azanidazole
- Tinidazoles
- Secnidazole
MOATS
Give 2 examples of Isoquinolines.
- Emetine
- Dehydroemetine
Mention 5 examples of hydroxyquinolines.
- Broxyquinoline
- Iodoquinol
- Clioquinol
- Chlorquinaldol
- Tibroquinol
BIC₂T
Mention 4 Dichloroacetamides used in amoebiasis treatment.
- Diloxanide
- Etofamide
- Clefamide
- Teclozan
Give an example of Aminoglycoside used in amoebiasis treatment.
Paromomycin
State the dosage and mechanism of action of Metronidazole.
400mg t.d.s ×10/7
MOA is unknown for E. histolytica but for anaerobic bacteria, it inhibits nucleic acid synthesis by disrupting DNA.
It has little effect on human cells and aerobic bacteria.
The MOA is the same for Tinidazole and Secnidazole
Mention 5 uses of Metronidazole
- Amoebiasis
- Giardiasis
- Trichomoniasis
- Bacterial vaginosis
- Eradication of H. pylori
- Prevention of post-surgical infection
Mention 5 side effects of metronidazole
- Nausea
- Diarrhoea
- Abdominal pains
- Vomiting
- Antabuse reaction
- Weight loss
- Dizziness
- Metallic taste
Same as Tinidazole and Secnidazole.
What is the dosage for Secnidazole?
1g (4 tabs) at once.
State the mechanism of action and use of Iodoquinol.
It acts by chelating the ferrous ions necessary for E. histolytica metabolism.
It is used to treat luminal amoebiasis.
What are the side effects of iodoquinol?
i. Diarrhoea
ii. Chills
iii. Hypersensitivity
iv. Enlargement of thyroid glands
v. Fever
What is the dosage for iodoquinol?
650mg tds ×20/7
What is the dosage and use of Diloxanide furoate?
500mg tds ×10/7
Luminal amoebiasis
Mention 3 side effects of Diloxanide furoate.
- Skin rash
- Flatulence
- Abdominal cramps
State the dosage and MOA of Paromomycin.
22-35mg/kg/day (divided into 3 doses) ×5-10/7
It inhibits protein synthesis by by binding to the 16S ribosomal RNA.
Mention 4 uses of paromomycin.
- Amoebiasis
- Leishmaniasis
- Cryptosporidiosis
- Bacterial infections
What are the side effects of paromomycin?
- Nausea
- Diarrhoea
- Abdominal cramps
How do you treat amoebic liver abscess?
Metronidazole 400mg tds ×10/7 (or Tinidazole 2g once daily ×6/7) PLUS Diloxanide furoate 500mg tds ×10/7 (or one of the other luminal amoebicides) must always be given afterwards.
