Randomized, double-blind comparison of a prochlorperazine-based versus a metoclopramide-based antiemetic regimen in patients undergoing autologous bone marrow transplantation.

Background: Highly emetogenic combination alkylator therapy is routinely used in autologous bone marrow transplantation for treatment of eligible patients with solid tumors. Antiemetic therapy remains less than optimal in this setting.

Methods: One hundred twenty-six patients with cancer receiving high dose cisplatin, cyclophosphamide, and carmustine with autologous bone marrow support were randomized to receive one of four double-blinded antiemetic regimens: 4-day continuous infusion prochlorperazine (6 mg/m2 intravenous [i.v.] loading dose followed by 1.5 mg/m2/hour) or metoclopramide (80 mg/m2 iv loading dose followed by 20 mg/m2/hr) each with either dronabinol 5 mg/m2 or placebo capsules for two doses before carmustine on the last day of chemotherapy. All subjects received scheduled lorazepam and diphenhydramine throughout the 4-day study period. Efficacy was measured by the Emetic Process Rating Scale and the Rhodes Index of Nausea and Vomiting (INV) Form 2.

Results: One hundred six patients completed the study and were fully evaluable. The median number of emetic episodes on the metoclopramide study arm were: 1 (0-7, day -6), 1 (0-6, day -5), 2 (0-9, day -4), and 2 (0-10, with dronabinol day -3) or 2 (0-7, no dronabinol day -3) and on the prochlorperazine study arm were: 4 (0-12, day -6), 0 (0-8, day -5), 0 (0-12, day -4) and 2.5 (0-9, with dronabinol day -3) or 2 (0-12, no dronabinol day -3). Metoclopramide was significantly better on the first day of therapy (day -6, P < .002) and prochlorperazine was significantly better on the third day of therapy (day -4, P < 0.002). There was no significant difference among any of the four arms on the last day of chemotherapy (day -3), or when the median number of emetic episodes over the total study period were compared. The patients' assessment of nausea, vomiting, and retching on the INV Form 2 was consistent with the observer ratings. Toxicities requiring dose reduction or discontinuation of antiemetic drugs included diarrhea, cardiac arrhythmias, sedation, anxiety, and akathisia.

Conclusions: Both metoclopramide and prochlorperazine in combination with lorazepam and diphenhydramine offer good control of nausea and vomiting although the sedation and low risk for cardiac toxicity limit the regimen to an inpatient setting with close monitoring. No regimen was clearly superior during the entire treatment period but prochlorperazine offered more consistent control after the first day.