Effect of schistosomiasis infection on the clearance of phenazone in mice.

The disposition phenazone (antipyrine) was used to study the effect of Schistosoma mansoni infection on the activity of drug metabolizing enzymes in mice. Plasma elimination rate constant (Ke), elimination half-life (t1/2e), clearance (CL) and apparent volume of distribution (Vd) were estimated 8 and 12 weeks after infection of mice with 80 S. mansoni cercariae. Liver and kidney function tests were performed simultaneously. Infection increased the levels of glutamic oxalacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), lactic dehydrogenase (LDH), alkaline phosphatase (AP) and total proteins 8 and 12 weeks post infection. At the same time a decrease was recorded in the total cholesterol level. Moreover infection with S. mansoni produced a decrease in phenazone clearance with an increase in the area under the curve (AUC) of the drug 8 and 12 weeks post infection. Elimination half-lives were 57.92 +/- 14.10 and 72.72 +/- 4.14 min 8 and 12 weeks after infection, respectively, compared to 19.29 +/- 3.30 and 26.14 +/- 5.31 min in corresponding controls. No statistically significant change was recorded in the volume of distribution of phenazone in the groups studied. In addition no significant correlation was found between parameters of phenazone disposition and the enzyme levels studied 8 and 12 weeks after infection.