1. To compare the effectiveness of gabapentin (titrated to300mg TID days -2 to 5) with aprepitant (125mg on day 1 and 80mg on days 2 and 3) in the control of delayed nausea and vomiting associated with level 3, 4 or 5 emetogenic chemotherapy in patients who experienced delayed nausea and/or vomiting during their first cycle of chemotherapy.