Pharmacokinetics of praziquantel in healthy volunteers and patients with schistosomiasis.
The pharmacokinetics of a novel praziquantel preparation (Distocide) were investigated in Sudanese patients with hepatosplenic schistosomiasis and in healthy volunteers, and compared with those of Biltricide. The results of the first study indicated greater (P less than 0.05) plasma concentrations of Biltricide at 1.5, 2, 3 and 5 h after administration than with Distocide; plasma elimination half-lives (t 1/2) were not significantly different. In patients with hepatosplenic schistosomiasis, higher plasma levels of Distocide were noted (P less than 0.05 at 8 h) compared to healthy controls; however, due to wide inter-individual variations, there were no significant differences in maximum plasma concentration, time to maximum plasma concentration, area under the plasma concentration curve (AUC), volume of distribution, or clearance; t 1/2 was greater (P less than 0.05) in patients (11.9 +/- 5.4 h) than controls (2.3 +/- 0.4 h). In the presence of food, higher plasma concentrations of Distocide occurred compared to the fasting state; AUCs were greater (P less than 0.01) in both food groups, although the values of t 1/2 were shorter. The lower plasma levels and longer duration of action of Distocide may be advantageous in reducing side effects and prolonging exposure of the schistosomes to the drug.