Systemic influence of intravesical chemotherapy with verapamil.

The influence of the calcium blocker verapamil (VR) on systemic toxicity resulting from the intravesical instillation of Adriamycin (ADM) and thiotepa (THT) was assessed in mice. Eighty per cent of the animals receiving THT + VR developed a generalized alopecia. Data gathered at necroscopy failed to reveal any trauma to the major organs or the presence of a drug-induced myelosuppression. Combination of ADM and VR did not produce an enhancement of systemic toxicity, manifest as myelosuppression. The drug combination did not produce a cardiomyopathy as assessed by histologic examination. The use of VR in combination with antineoplastic agents posed no more of a threat to the animals than did the use of cytotoxin alone.