What is secnidazole? What is the effect of secnidazole on abscesses with Entamoeba Histolytica?/nTh

Fråga: What is secnidazole? What is the effect of secnidazole on abscesses with Entamoeba Histolytica?

The background is that a 29-year-old patient, who was treated with secnidazole in Kenya, is now presenting with two amoeba abscesses in the liver and possibly one in a lung.

Sammanfattning: Secnidazole is an antiprotozoal agent not approved in Sweden. It is known to have a good clinical effect in amoeba infections, even in single dose due to its long elimination half-life. A literature search in Medline has not revealed any information specifically about secnidazole in treatment of liver abscess.

The drug of choice in Sweden for amoebic infections is metronidazole. In the international literature chloroquine is reported to be beneficial against amoebiasis, especially in liver ascess.

Svar: Secnidazole is an antiprotozoal agent not approved by the Medical Products Agency in Sweden. It has properties similar to those of metronidazole and tinidazole (1). These drugs share a common spectrum of activity against anaerobic micro-organisms and they appear to be particularly effective in the treatment of amoebiasis, giardiasis and trichomoniasis. However, secnidazole has a longer terminal elimination half-life than other drugs in the same class, that is approximately 17-29 hours compared to eg, metronidazole that has a half-life of approximately 8 hours (2). The longer half-life of secnidazole allows single-dosage or once daily administration (3). This makes secnidazole convenient to apply in developing countries (4).

Patients with hepatic amoebiasis appears to respond well to 5- to 7-day therapy with secnidazole (2). In a study that determined the clinical efficacy of secnidazole in the treatment of acute and chronic cases of amoebiasis, patients were given 2g in a single dose or in two divided doses within a 4h interval. Results were analyzed for 45 chronic and five acute cases and showed a clinical cure of 98 per cent in chronic and 80 per cent in acute cases. The treatment regimen proved effective for the eradication of E Histolytica and only two (4 per cent) remained positive after treatment out of the 50 patients initially positive (5).

In Sweden, the drug of choice for amoebiasis, with or without liver abscess, is metronidazole which is proved to be more effective than tinidazole (6). Chloroquine has been given, especially in combinations with other antiamoebicals, to cases that fail to respond to metronidazole. Chloroquine has its value above all in amoebic liver abscess, propably due to the high concentration it achieves in the liver. Furthermore, antibiotics, for example tetracycline have some therapeutic action as well, however mostly in the intestinal tract (7).

Neither secnidazole nor metronidazole are inhibitors of the cytochrome system (8). Unfortunately, there is not a method available for plasma drug concentration of metronidazole. 1 Martindale, The extra pharmacopoeia. 1996; 31th ed: 629 2 Gillis JC, Wiseman LR: Secnidazole. A review of its antimicrobial activity, pharmacokinetic properties and therapeutic use in the management of protozoal infections and bacterial vaginosis. Drugs 1996; 51: 621-38 3 Rossignol JF, Maisonneuve H, Cho YW: Nitroimidazoles in the treatment of trichomoniasis, giardiasis, and amebiasis. Int J Clin Pharmacol Ther Toxicol 1984; 22: 63-72 4 Cesari J, Condat M, Gendron Y, Saint-Andre P, Thomas J, Charmot G: Treatment of amibiasis with short-term secnidazole therapy. Med Trop 1982; 42: 527-30 5 Latonio AA: Efficacy of a single dose of secnidazole in the treatment of acute and chronic amoebiasis. J Trop Med Hyg 1988; 91: 202-4 6 Nordbring F: Antibiotika och kemoterapi. Almqvist och Wiksell 1991 7 James DM, Gilles HM: Human antiparasitic drugs pharmacology and usage. John Wiley and Sons 1985 8 Forgue-Lafitte ME, Coudray AM, Fagot D: Effects of ketoconazole on the proliferation and cell cycle of human cancer cell lines. Cancer Res 1992; 52: 6827-31