Results
Of the 124 patients initially screened through pharmacy dispensing records, 88 were excluded. The most common reasons for exclusion were olanzapine use as part of a four-drug CINV regimen, chemotherapy as part conditioning regimen for transplant, or chemotherapy was classified as moderately emetogenic. A total of 36 unique patients and total of 82 chemotherapy blocks met inclusion criteria. Baseline characteristics and demographic data are presented in Table 1. In the acute phase, CR was achieved in 22 (52%) patients in the olanzapine group versus 25 (63%) in the dexamethasone group (p=0.354). There was no clinically or statistically significant difference in CR rates between olanzapine and dexamethasone groups (Table 2).
Ondansetron 0.15 mg/kg (maximum 8 mg) every 8 hours was the 5-HT3 antagonist used in all but two of the chemotherapy blocks in the dexamethasone group. Palonosetron 0.02 mcg/kg (maximum 0.25 mg) for one dose was administered to those that didn’t receive ondansetron. Fosaprepitant was dosed per package insert for one dose and one patient in the olanzapine group received two doses of fosaprepitant 72 hours apart. In the dexamethasone group, dexamethasone was dosed at 5 mg/m2 once daily for the duration of chemotherapy.
The mean initial olanzapine dose was 0.07 mg/kg/dose (range 0.02-0.1, maximum 5 mg). Doses were rounded to nearest 1.25 mg. The median duration of olanzapine was 2 days (range 1-7 days). Olanzapine was initiated on day 1 of chemotherapy for all blocks and was continued for the duration of each chemotherapy block or longer in 28 (67%) blocks. No patients required a dose reduction of olanzapine due to intolerance; 3 patients required a dose increase to maximize efficacy. Olanzapine was discontinued in one of two patients for over-sedation.