General Effectiveness Of The Treatment Plan Of Amoebiasis Infection

Specific treatment consists of amoebicidal drugs. These may act on the parasites found in the lumen of the gut or on the invasive forms seen in the tissues. They are grouped as luminal amoebicides and tissue amoebicides. Some drugs, however, have action on both the sites. The most effective amoebicides in current uses are given in the following examples below.

1. Metronidazole: 400mg, 3 times/day orally for 10 days or 800mg twice daily for 5 days.
2. Emetine: 60 mg intramuscular, daily for 10 days.
3. Dehydroemetine: 90mg intramuscular daily for 10 days.
4. Diloxanide furoate: 500 mg, 3 times daily for 10 days.
5. Chloroquine: 500mg, twice daily for 2 days followed by 250 mg twice daily for 19 days orally.
6. Tinidazole: 600mg, twice daily for 5 days orally.

The iodohydroxyquinolines which were extensively used to treat chronic intestinal amoebiasis have fallen into disfavor following reports of subacute myelo-optic neuropathy (SMON) mainly from Japan. However, in India, this complication was only rarely encountered.

Metronidazole

This drug has effect on both trophozoites and cysts. It is well-absorbed after an oral dose to produce adequate tissue levels. This drug can be used for the treatment of acute and chronic intestinal amoebiasis and in hepatic amoebiasis. In severe cases, the drug can be used intravenously in a dose of 500mg thrice a day as an infusion. Though, side effects are not serious, they are common. These include distaste in the mouth, anorexia, nausea, abdominal discomfort, vertigo, dizziness and ataxia. Peripheral neuropathy may develop rarely. Peripheral neuropathy may develop rarely. The drug is generally avoided during pregnancy on account of its possible teratogenic effects seen in laboratory animals.

Emetine

It is a powerful amoebicide, effective against the trophozoites in intestinal and extraintestinal amoebiasis. It produces rapid relief in acute amoebic dysentery, liver abscess and other tissue forms of the disease. It is ineffective against cysts. Therefore, it does not eradicate chronic intestinal lesions. Emetine has to be given intramuscularly in a dose of 60 mg/day. The drug is cumulative and, therefore the total dose in a course should be limited to 600 mg. Local necrosis at the site of injection and cardiac toxicity are serious drawbacks. Toxic myocarditis may present with hypotension, cardiac failure, heart block and other serious arrhythmias. Due to this risk, emetine should be avoided in patients with pre-existing heart disease and in old debilitated subjects. Emetine is seldom used now. Only in special indications like hepatic abscess, cutaneous amoebiasis or cerebral and pulmonary amoebiasis. It is given when metronidazole proves unsatisfactory.

Dehydroemetine

It is a synthetic derivative of emtine, which is slightly less potent by has lower cardiotoxicity. It is more widely used than emetine.

In spite of the grave toxic effects, judicious use of emetine and its derivative has saved many patients with advanced severe amoebic lesions.

Dilosanide furoate

It is a safe drug effective only on the intestinal forms of the parasite. It is used in the treatment of acute and chronic intestinal lesions. In amoebic dysentery, the symptoms subside in 5 to 7 days. In chronic intestinal amoebiasis, clearance rates approximate 80 to 90%.

Chloroquine

It has amoebicidal properties in hepatic lesions. This is brought about by the high tissue concentration of the drug about by the high tissue concentration of the drug obtained in the liver. It is effective in the treatment of hepatic amoebiasis along with metronidazole or emetine. It has no action on the trophozoites or cysts in the intestine.

Tinidazole

This drug belongs to the group of nitroimidazole derivatives, structurally related to metronidazole. The therapeutic spectrum is similar to metronidazole, but the drug is more potent. It is also better tolerated.