[Antineoplastic activity of drugs affecting the central nervous system against chemically induced tumors in the rat (author's transl)].

Piracetam and Pyrithioxin, drugs affecting the central nervous system, prolonged survival times in rats with the 3-MC sarcoma. Tumor remissions were observed in several male animals. We were able to achieve a high survival rate without metastasis after surgical removal of the tumors. The remission rate could be increased 6-fold when Piracetam was combined with Cyclophosphamid. In this group male and female animals reacted in the same manner. When used prophylactically, Piracetam proved to be more effective than Pyrithioxin. The effectiveness of Piracetam depended on the onset of treatment. Tumor remission was significant 28 weeks following 3-MC injection when 3-MC and Piracetam were given simultaneously. A remarkable increase of the tumor rate ensued when medication was discontinued. The tumor rate decreased to less than 50% 36 weeks following 3-MC injection if treatment was started 8 weeks following 3-MC application. The latter applied only to Piracetam and not to Pyrithioxin. In the EEG of rats the diminished amplitude induced by 3-MC could be fully compensated by 100 mg/kg Piracetam. All animals treated in this manner for 7 months remained tumor-free.