An amebicide (or amoebicide) is an agent that is destructive to
amoeba
An amoeba (; less commonly spelled ameba or amœba; plural ''am(o)ebas'' or ''am(o)ebae'' ), often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudo ...
, especially parasitic amoeba that cause
amoebiasis
Amoebiasis, or amoebic dysentery, is an infection of the intestines caused by a parasitic amoeba ''Entamoeba histolytica''. Amoebiasis can be present with no, mild, or severe symptoms. Symptoms may include lethargy, loss of weight, colonic ulce ...
.
Entamoeba
*
Metronidazole
Metronidazole, sold under the brand name Flagyl among others, is an antibiotic and antiprotozoal medication. It is used either alone or with other antibiotics to treat pelvic inflammatory disease, endocarditis, and bacterial vaginosis. It is e ...
, or a related drug such as
Tinidazole
Tinidazole is a drug used against protozoan infections. It is widely known throughout Europe and the developing world as a treatment for a variety of anaerobic amoebic and bacterial infections. It was developed in 1972 and is a prominent member of ...
,
Secnidazole
Secnidazole (trade names Flagentyl, Sindose, Secnil, Solosec) is a nitroimidazole anti-infective. Effectiveness in the treatment of dientamoebiasis has been reported. It has also been tested against '' Atopobium vaginae''.
In the United States, ...
or
Ornidazole
Ornidazole is an antibiotic used to treat protozoan infections. A synthetic nitroimidazole, it is commercially obtained from an acid-catalyzed reaction between 2-methyl-5-nitroimidazole and epichlorohydrin. Antimicrobial spectrum is similar to th ...
, is used to destroy amoebae that have invaded tissue.
* Several drugs are available for treating intestinal infections, the most effective of which has been shown to be
Paromomycin
Paromomycin is an antimicrobial used to treat a number of parasitic infections including amebiasis, giardiasis, leishmaniasis, and tapeworm infection. It is a first-line treatment for amebiasis or giardiasis during pregnancy. Otherwise it is ge ...
(also known as Humatin).
''E. histolytica'' infections occur in both the intestine and (in people with symptoms) in tissue of the intestine and/or liver.
As a result, both tissue and luminal drugs are needed to treat the infection, one for each location. Metronidazole is usually given first, followed by
Paromomycin
Paromomycin is an antimicrobial used to treat a number of parasitic infections including amebiasis, giardiasis, leishmaniasis, and tapeworm infection. It is a first-line treatment for amebiasis or giardiasis during pregnancy. Otherwise it is ge ...
or
Diloxanide
Diloxanide is a medication used to treat amebiasis, amoeba infections. In places where infections are not common, it is a second line treatment after paromomycin when a person has no symptoms. For people who are symptomatic, it is used after tre ...
.
''E. dispar'' does not require treatment, but many laboratories (even in the developed world) do not have the facilities to distinguish this from ''E. histolytica''.
Tissue amebicides
Metronidazole
Metronidazole, sold under the brand name Flagyl among others, is an antibiotic and antiprotozoal medication. It is used either alone or with other antibiotics to treat pelvic inflammatory disease, endocarditis, and bacterial vaginosis. It is e ...
, or a related drug such as
tinidazole
Tinidazole is a drug used against protozoan infections. It is widely known throughout Europe and the developing world as a treatment for a variety of anaerobic amoebic and bacterial infections. It was developed in 1972 and is a prominent member of ...
,
secnidazole
Secnidazole (trade names Flagentyl, Sindose, Secnil, Solosec) is a nitroimidazole anti-infective. Effectiveness in the treatment of dientamoebiasis has been reported. It has also been tested against '' Atopobium vaginae''.
In the United States, ...
or
ornidazole
Ornidazole is an antibiotic used to treat protozoan infections. A synthetic nitroimidazole, it is commercially obtained from an acid-catalyzed reaction between 2-methyl-5-nitroimidazole and epichlorohydrin. Antimicrobial spectrum is similar to th ...
, is used to destroy amoebae that have invaded tissue.
[ These are rapidly absorbed into the bloodstream and transported to the site of infection. Because they are rapidly absorbed there is almost none remaining in the intestine.
For amebic dysentery a multi-prong approach must be used, starting with one of:
* ]metronidazole
Metronidazole, sold under the brand name Flagyl among others, is an antibiotic and antiprotozoal medication. It is used either alone or with other antibiotics to treat pelvic inflammatory disease, endocarditis, and bacterial vaginosis. It is e ...
500–750 mg three times a day for 5–10 days
* tinidazole
Tinidazole is a drug used against protozoan infections. It is widely known throughout Europe and the developing world as a treatment for a variety of anaerobic amoebic and bacterial infections. It was developed in 1972 and is a prominent member of ...
2g once a day for 3 days is an alternative to metronidazole
Doses for children are calculated by body weight and a pharmacist should be consulted for help.
Luminal amebicides
Since most of the amoebae remain in the intestine when tissue invasion occurs, it is important to get rid of those also or the patient will be at risk of developing another case of invasive disease. Several drugs are available for treating intestinal infections, the most effective of which has been shown to be paromomycin
Paromomycin is an antimicrobial used to treat a number of parasitic infections including amebiasis, giardiasis, leishmaniasis, and tapeworm infection. It is a first-line treatment for amebiasis or giardiasis during pregnancy. Otherwise it is ge ...
(also known as Humatin); iodoquinol
The quinoline derivative diiodohydroxyquinoline (INN), or iodoquinol ( USAN), can be used in the treatment of amoebiasis.
It is poorly absorbed from the gastrointestinal tract and is used as a luminal amebicide. It acts by chelation of ferrous ...
(also known as Yodoxin) is used in the US; and diloxanide furoate
Diloxanide is a medication used to treat amoeba infections. In places where infections are not common, it is a second line treatment after paromomycin when a person has no symptoms. For people who are symptomatic, it is used after treatment wi ...
(also known as Furamide) is used in certain other countries.
In addition to the tissue amebicides above, one of the following lumenal amebicides should be prescribed as an adjunctive treatment, either concurrently or sequentially, to destroy ''E. histolytica
''Entamoeba histolytica'' is an anaerobic parasitic amoebozoan, part of the genus ''Entamoeba''. Predominantly infecting humans and other primates causing amoebiasis, ''E. histolytica'' is estimated to infect about 35-50 million people worldw ...
'' in the colon:
* Paromomycin
Paromomycin is an antimicrobial used to treat a number of parasitic infections including amebiasis, giardiasis, leishmaniasis, and tapeworm infection. It is a first-line treatment for amebiasis or giardiasis during pregnancy. Otherwise it is ge ...
500 mg three times a day for 10 days
* Iodoquinol
The quinoline derivative diiodohydroxyquinoline (INN), or iodoquinol ( USAN), can be used in the treatment of amoebiasis.
It is poorly absorbed from the gastrointestinal tract and is used as a luminal amebicide. It acts by chelation of ferrous ...
650 mg three times a day for 20 days
Doses for children are calculated by body weight and a pharmacist should be consulted for help.
Amebic liver abscess
For amebic liver abscess:
* Metronidazole 400 mg three times a day for 10 days
* Tinidazole 2g once a day for 6 days is an alternative to metronidazole
* Diloxanide furoate 500 mg three times a day for 10 days (or one of the other lumenal amebicides above) must always be given afterwards
Doses for children are calculated by body weight and a pharmacist should be consulted for help.
Acanthamoeba
Propamidine isethionate
Propamidine is an antiseptic and disinfectant.
Propamidine isethionate, the salt of propamidine with isethionic acid, is used in the treatment of ''Acanthamoeba
''Acanthamoeba'' is a genus of amoebae that are commonly recovered from soil, fre ...
has been used in the treatment of Acanthamoeba
''Acanthamoeba'' is a genus of amoebae that are commonly recovered from soil, fresh water, and other habitats.
''Acanthamoeba'' has two evolutive forms, the metabolically active trophozoite and a dormant, stress-resistant cyst. Trophozoites are ...
infection.
Treatment by use of primitive medicines
The Nicobarese people
The Nicobarese people are an Austroasiatic-speaking people of the Nicobar Islands, a chain of islands in the Bay of Bengal north of Sumatra, forming part of the union territory of Andaman and Nicobar Islands, India. Only 12 of the 19 islands ar ...
have attested to the medicinal properties found in ''Glochidion calocarpum
''Glochidion'' is a genus of flowering plants, of the family Phyllanthaceae, known as cheese trees or buttonwood in Australia, and leafflower trees in the scientific literature. It comprises about 300 species, distributed from Madagascar to the ...
'', a plant endemic to India, saying that its bark and seed are most effective in curing abdominal disorders associated with amoebiasis
Amoebiasis, or amoebic dysentery, is an infection of the intestines caused by a parasitic amoeba ''Entamoeba histolytica''. Amoebiasis can be present with no, mild, or severe symptoms. Symptoms may include lethargy, loss of weight, colonic ulce ...
.[See p. 412 in: ]
''Naegleria''
Although ''Naegleria
''Naegleria'' is a free living amoebae protist genus consisting of 47 described species often found in warm aquatic environments as well as soil habitats worldwide. It has three life cycle forms: the amoeboid stage, the cyst stage, and the flage ...
'' is sometimes considered amoeboid
An amoeba (; less commonly spelled ameba or amœba; plural ''am(o)ebas'' or ''am(o)ebae'' ), often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudopo ...
, unlike Acanthamoeba or Balamuthia
''Balamuthia mandrillaris'' is a free-living amoeba that causes the rare but deadly neurological condition granulomatous amoebic encephalitis (GAE). ''B. mandrillaris'' is a soil-dwelling amoeba and was first discovered in 1986 in the brain of ...
it is not closely related to the Amoebozoa (it is much more closely related to ''Leishmania
''Leishmania'' is a parasitic protozoan, a single-celled organism of the genus '' Leishmania'' that are responsible for the disease leishmaniasis. They are spread by sandflies of the genus ''Phlebotomus'' in the Old World, and of the genus '' ...
'') and agents used to treat ''Naegleria'' infections are usually addressed separately.
See also
* Anti-protist
Anti-protist or antiprotistal refers to an anti-parasitic and anti-infective agent which is active against protists. Unfortunately due to the long ingrained usage of the term antiprotozoal
Antiprotozoal agents ( ATC code: ATC P01) is a class o ...
References
External links
*
{{Agents against amoebozoa
Amoebozoa