A biochemical basis for the radiosensitizing and cytotoxic effects of chlorpromazine hydrochloride in vitro and in vivo.

There have been many investigations on the radiosensitizing and cytotoxic effects of chlorpromazine, both in vitro and in vivo. We have extended the studies to include the chemotherapeutic effect of chlorpromazine on lymphosarcoma and on a mammary adenocarcinoma arising spontaneously in breeding female CBA mice. Chlorpromazine was ineffective in the former tumor but enhanced the longevity of tumor-bearing mice in the latter case. The drug was also observed to potentiate the hyperthermic killing of L5178Y cells and inhibit cellular oxygen utilization by cultured mammalian cells. The possible mechanisms involved are discussed.