There were no differences in the number of patients with hypotension in the placebo ( @ % ) and ondansetron @mg ( @ % ) , @ mg ( @ % ) and @ mg ( @ % ) groups ( P = @ ) , nor the percentage of time points with systolic hypotension ( @ % in the placebo group and @ % , @ % and @ % in the ondansetron @ , @ and @ mg groups , respectively , P = @ ) .