Compliance with guidelines results in appropriate ondansetron prescribing at Christchurch Hospital

To assess compliance with established consensus derived guidelines for ondansetron therapy and to estimate the cost of any non-guideline use.

All inpatients (including paediatric patients) at Christchurch Hospital who received ondansetron during August 1993 were identified by daily review of medication charts. Outpatients who received ondansetron prescriptions were identified from pharmacy records. All patients' medical records were then examined and ondansetron therapy was compared with the guideline recommendations for indication and dosage. The total cost of ondansetron for each patient was also calculated.

Ondansetron was prescribed for 64 patients (41 female, 23 male) during the one month period. Fifty patients received ondansetron therapy in accordance with all indication and dosage aspects of the guidelines. The main guideline indication for use was highly emetogenic chemotherapy with 28 patients. Fifteen patients received ondansetron because of failure of standard antiemetic therapy and nine because they were paediatric chemotherapy patients. Of the 12 patients who received ondansetron outside the guidelines indications, nine had received 'moderately highly' emetogenic chemotherapy (whereas the guidelines state 'highly' only), two had severe asthma, one received radiotherapy. Two patients did not comply with the dosage recommendations as they received ondansetron more than 24 hours after the initial cytotoxic dose. Total ondansetron expenditure for the period was $12,789 (inpatient $8492 outpatient $4297). Expenditure related to the nonguideline usage was $536 (4.2% of the total monthly ondansetron expenditure).

There was high compliance with the guidelines. This supports the use of guidelines in encouraging appropriate prescribing.