Hepatic amoebiasis, treatment

An amoebic abscess of the liver is treated with metronidazole for 10 days (often initially IV), followed by diloxanide furoate for 10 days. The latter is to destroy any amoebae in the lumen of the intestines. Chloroquine is moderately active on liver abscesses and may in some cases be administered. If the diagnosis is known, aspiration is only carried out for very large abscesses or if there is a risk of breakthrough. Surgery is indicated if the abscess ruptures (e.g. into the peritoneum). If a relapse of the abscess occurs this will usually happen within two months.

In case of resistance to metronidazole the quite toxic drug emetine may be used. Emetine is administered by deep intramuscular or subcutaneous route: 1 mg/kg/day with maximum of 60 mg/day. Emetine has been used since 1912 in the treatment of amoebiasis. It is an alkaloid from the roots and rhizomes of ipecac (Cephaelis ipecacuanha (Brazil) and C. acuminata (Central America and Colombia). These shrubs belong to the plant family of Rubiaceae and are also known as Uragoga ipecacuanha or Psychotria ip. The plant was known in earlier times. In 1682 the son of the French king Louis XIV recovered from severe dysentery after taking extracts of this plant. The active alkaloid was identified in 1817.

Emetine induces nausea and vomiting, from which it has its name, and is only rarely administered orally. After parenteral administration absorption is rapid, but excretion is slow. Traces of emetine can still be recovered in tissues up to 60 days after a treatment.

Tachycardia and dizziness after a single administration are signs of hypersensitivity to the drug. Emetine is cytotoxic, including for the myocardium. Signs of intoxication are as follows:

• Nausea, vomiting and diarrhoea, although occurrence of these does not mean that the treatment has failed.

• Palpitations, tachycardia, retrosternal pain, hypotension, dyspnoea, ECG changes (ST depression, QT prolongation, T-wave inversion). The ECG returns to normal 1 to 2 weeks after discontinuation of the injections.

• Asthenia, tremor, myasthenia and paralysis including respiratory paralysis.

Treatment must not be repeated within six weeks following the initial treatment. Emetine must not be combined with other drugs which are toxic for the myocardium. The drug is preferably administered by deep subcutaneous injection and this is painful. IM administration may result in muscle necrosis which heals slowly and may lead to formation of fistulae and permanent scars. The drug is not administered IV. Contraindications are organic heart disease and conditions of advanced asthenia. The treatment is not without risk in children and the elderly, and in debilitated or undernourished patients. Admission and strict bed rest are necessary. Emetine is very effective in amoebic dysentery and amoebic abscess of the liver, but contact amoebicides should be used to supplement the treatment.

Dehydroemetine is better than emetine. Dehydroemetine is a semi-synthetic product with is more rapidly eliminated and has fewer side-effects. Recommended doses are between 1 mg/kg/day IM for 5 days and 2 mg/kg/day (maximum 90 mg/day) for not more than 15 days (two injections daily). Oral administration is sometimes recommended with tablets of 10 mg DHE which are slowly soluble. The same doses are used for oral and parenteral administration.

Category: Medicine Notes