Effect of the centrally acting antitussives on ascites tumor cells.

Dextromethorphan, dimemorfan, dihydrocodeine and oxymethebanol, centrally acting antitussives, were examined for their effect on Ehrlich carcinoma cells and sarcoma-180 cells in vitro or in vivo. The tumor cells were suspended in Hanks balanced salt solution (pH 7.4) supplemented with 2% bovine albumin, and they were incubated with and without 1 mM drugs at 37 degrees C for 120 min. The incubation of the tumor cells with dextromethorphan or dimemorfan resulted in a decrease in the proportion of the viable cells (less than 25% after 120 min). However, no significant change was observed in the proportion of the viable tumor cells during the incubation with and without the other drugs (80-83% after 120 min). In addition, mice given the tumor cells i.p. were injected intraperitoneally with drugs (20-80 mg/kg/day) once daily for 5 successive days, and their survival time was observed. There was a slight difference in the survival time between mice treated with and without dextromethorphan or dimemorfan. However, a significant difference was found in the survival time between mice treated with and without dextromethorphan when mice given Ehrlich carcinoma cells were injected with the drug (40 mg/kg/time) twice a day for 5 days (about 18 days and 29 days). These results indicate that dextromethorphan and dimemorfan are cytotoxic to the tumor cells in vitro and in vivo.