[Intravesical instillation of combined adriamycin and verapamil in preventing recurrence of superficial bladder tumor].

Multidrug-resistance of the tumor cells is the main cause for failure of chemotherapy. Such resistance is correlated to P-glycoprotein 170, which can pump the chemotherapeutic agent out of the tumor cells. This action could be reversed by verapamil through competition for closely related binding sites on P-glycoprotein. Twenty-four postoperative cases of superficial bladder tumors were treated by intravesical instillation of combined adriamycin and verapamil, and they were followed up for 17-35 months (average 24.5 months). Two cases (8.7%) had recurrence. NO marked toxicity and side-effects were observed. Verapamil working as a drug-resistance reversing agent might be used in some other tumors not sensitive to chemotherapy.