ALBUQUERQUE--Oncologists and pharmacists at the University of New Mexico initially turned to reduced-dose ondansetron(Drug information on ondansetron) (Zofran) for their pediatric leukemia patients for sheer expediency--most of the children were receiving their chemotherapy as outpatients and were only in the clinic for about 4 hours per treatment.
This made it impossible to give the recommended intravenous ondansetron dosage of 0.15 mg/kg every 4 hours for three doses during the outpatient visit.
"We settled on two doses and demonstrated efficacy for quite a few chemotherapy protocols, with a very good side effect profile," Mark T. Holdsworth, PharmD, assistant professor, College of Pharmacy, University of New Mexico, told Oncology News International in an interview.
The New Mexico investigators evaluated 255 courses of emetogenic chemotherapy in 16 pediatric outpatients with ALL. No antiemetic therapy was administered with 149 courses (primarily because, before ondansetron became available, patients often refused antiemetic therapy due to lack of perceived benefit). Two doses of IV ondansetron, 0.15 g/kg, were given with 106 courses, one dose prior to and one dose immediately following each course.
Fourteen patients received an intensive ALL regimen with both IV and intrathecal chemotherapy, and two patients received a low-risk ALL regimen with only intrathecal treatments.
Intrathecal therapy consisted of methotrexate(Drug information on methotrexate), hydrocortisone(Drug information on hydrocortisone), and cytarabine. Patients on intensive regimens also received sequential IV courses of cyclophosphamide(Drug information on cyclophosphamide) (Cytoxan, Neosar), daunorubicin(Drug information on daunorubicin) (Cerubidine), carmustine(Drug information on carmustine) (BiCNU), and a combination of cytarabine(Drug information on cytarabine) and etoposide(Drug information on etoposide) (VePesid).
Ondansetron provided complete protection against nausea and vomiting for more than 60% of the courses of carmustine and etoposide/cytarabine, and complete protection against vomiting for more than 55% of the courses of cyclophosphamide, Dr. Holdsworth said. These agents or combinations represent three of the four most emetogenic treatments examined in the study.