oxamniquine

Oxamniquine (OXA) has been the cornerstone of Brazilian schistosomiasis control programs during the last 25 years and still is one of the two commercially available drugs that are effective against Schistosoma mansoni (Coura & Amaral 2004, WHO 2002).  Available information on the mechanism of action of OXA (and of the related agent hycanthone) suggests that the drug becomes active only upon transformation to an alkylating agent by an enzyme that is present in OXA-sensitive schistosomes (reviewed in Cioli et al. 1995). The evidence originates from genetic crosses between OXA-sensitive and OXAresistant S. mansoni showing that resistance is a recessive trait, thus implying the existence of a parasite factor that is required for drug activity (Cioli et al. 1992).

In addition, a soluble extract from sensitive worms (but not from resistant worms) was capable of converting OXA into an alkylating agent that could bind covalently to the DNA and other macromolecules of the parasite (Pica-Mattoccia et al. 1989, 1992). Extracts from S. japonicum or S. haematobium (which are not sensitive to OXA), as well as extracts from mammalian tissues, failed to activate OXA. The OXA activating factor was clearly an enzyme, since it was thermolabile, protease sensitive, inactive at 0°C and required ATP + Mg2+ in a cell-free assay (Pica-Mattoccia et al. 1992). The precise nature of the enzyme, however, was not determined, except for the broad assumption that it might be an esterifying enzyme targeting the hydroxymethyl group that is present in the drug and  essential for its activity (Cioli et al. 1985).

Gambar 1. Struktur Oxamniquine

DAFTAR PUSTAKA

Cioli D, Pica-Mattoccia L, Moroni R 1992. Schistosoma mansoni: hycanthone / oxamniquine resistance is controlled by a single autosomal recessive gene. Exp Parasitol 75: 425-432.

Cioli D, Pica-Mattoccia L, Archer S 1995. Antischistosomal drugs: past, present ... and future? Pharmacol Ther 68: 35- 85.

Coura JR, Amaral RS 2004. Epidemiological and control aspects of schistosomiasis in Brazilian endemic areas. Mem Inst Oswaldo Cruz 99 (Suppl. 1): 13-19.

DAFTAR PERTANYAAN : 

 

   1.  Apakah efek samping dari oxamniquine?

   2.    Apakah obat ini masih dapat digunakan sebagai lini pertama dari penyakit skistosomiasis?

   3.    Apakah efek fatal dari penyakit skistosomiasis jika tidak diketahui dan tidak berikan pengobatan?