Progressive loss of antiemetic efficacy during subsequent courses of chemotherapy.

The maintenance of the antiemetic efficacy of a combined protocol (intravenous methylprednisolone, oral thiethylperazine and oral amitriptyline) during six consecutive courses of adjuvant FAC chemotherapy (5-fluorouracil, doxorubicin, cyclophosphamide) was analysed in 107 female breast cancer patients who completed the six planned courses of treatment. A continuous decrease in complete (no vomiting episodes) and major protection rate (0-2 vomiting episodes) was evident during chemotherapy. Complete protection rate decreased from 62.6% in the first course to 48.6% in the sixth (P less than 0.05, chi 2 test). The respective figures for major protection rate were 76.6% and 58% (P less than 0.01, chi 2 test). These data, together with other from the literature, should be taken into consideration when reviewing the overall results of current antiemetic trials, which usually only mention the results obtained in the first course of chemotherapy.