PRAZIQUANTEL (ANTISCHISTOSOMAL DRUG) - IS IT CLASTOGENIC, COCLASTOGENIC OR ANTICLASTOGENIC

Schistosoma haematobium infection is the most common health problem in Egypt. It is strongly associated with the development of urinary blad der carcinoma. The actual cause for the development of cancer is still under investigations, it can be due to mechanical irritation from sch istosomiasis ova, the infection itself or the drugs which are used to treat the patients. Praziquantel (PQ) is a commonly used drug to treat schistosomiasis patients. In mice, an in vivo cytogenetic study showe d that PQ is not clastogenic in mice. The frequency of micronuclei in all the study groups were insignificantly different from the control g roup (p > 0.05). However, it enhanced the clastogenicity of benzene at a very high dose. Results from combined exposure with benzene and PQ enhanced the metabolism of benzene to form muconaldehyde which may be responsible for the enhancement effect. In schistosomiasis patients, t wo cytogenetic studies were carried out before and after treatment wit h PQ. There was no significant increase in CAs in patients compared wi th the controls (p > 0.05). The frequency of MN was significantly high er in the infected persons (0.59 +/- 0.44) than the control individual s (0.23 +/- 0.23)(p < 0.05). After treatment, there was no significant change in both parameters. The other study was conducted to determine whether infection with this parasite resulted in an increase of chrom osomal breakage, micronuclei, in exofoliated urothelial cells. Micronu cleus frequencies were significantly higher in the infected group (mea n frequency, 0.84 +/- 0.69%) than among controls (mean frequency, 0.12 +/- 0.21%, p < 0.001). Micronucleus frequencies were higher in infect ed individuals who smoked compared with those who were non-smokers, al though this effect was not significant (p > 0.05). The mean micronucle us frequencies were reduced significantly in the group of patients who were followed up (before treatment, 0.80 +/- 0.70%, after treatment, 0.19 +/- 0.23%, p < 0.001), thus supporting a direct involvement of th e infection in increased chromosomal breakage in the urothelium and pr ovide proof of the role of PQ in decreasing the risk of cancer develop ment. At this stage, we still need to study the cytogenetic effect of human exposure to environmental agents such as pesticides, smoking, et c., together with treatment with PQ.