A brief therapeutic regimen of
praziquantel, reduced to a single day, has been effective for treatment of
neurocysticercosis. To study its pharmacokinetic characteristics, levels of
praziquantel in plasma were determined for eight healthy volunteers after the administration of three oral doses of 25 mg/kg of
body weight given at 2-h intervals, alone and with the simultaneous administration of
cimetidine. Each volunteer received both regimens in a randomized crossover design. Blood samples were taken during a period of 12 h, and
praziquantel concentration was measured by high-performance liquid chromatography. Levels of
praziquantel in plasma remained above 300 ng/ml during a period of 12 h; they increased 100% when
cimetidine was jointly administered. Compared with other regimens, the high levels obtained and the longer duration of action seem to be advantageous in prolonging the exposure of the parasites to the
drug and support previous clinical experience showing that the treatment of
neurocysticercosis with
praziquantel can be reduced from 2 weeks to 1 day with the
drug still retaining its cysticidal properties. Moreover, simultaneous administration of
praziquantel and
cimetidine could improve further the efficacy of the single-day
therapy for
cysticercosis and other
parasitic diseases, such as
schistosomiasis.