Paradoxical effects of prophylactic phenothiazine antiemetics in children receiving chemotherapy.

The effectiveness of prophylactic phenothiazine antiemetics on reduction of nausea and vomiting was assessed for 23 children (age, 9-17 years) who had intermittently received antiemetics (ie, for one course but not for another). Each patient was his own control and the courses with antiemetics were compared to the matched courses without antiemetics (Wilcoxon matched-pairs, signed-ranks test). In each case, the matched courses with and without antiemetics were temporally consecutive and equivalent for chemotherapeutic agents and dosages. Significantly higher ratings for severity of nausea (P less than .004), vomiting (P less than .02), and the extent to which these symptoms bothered patients (P less than .001) were found during courses with prophylactic antiemetics. Duration (in hours) of nausea and vomiting was analyzed for the last eight consecutive study patients; in eight of eight patients, a significantly longer duration of nausea (P less than .05) and vomiting (P less than .02) was found for the courses in which antiemetics were given prophylactically. This study suggests that prophylactic phenothiazine antiemetics do not predictably reduce children's nausea and vomiting and may even be associated with an increase in symptoms. Further studies in children are needed to determine which patients might benefit most from antiemetic intervention.