OBJECTIVES: Since the Palliative Care Service started at MD Anderson Cancer Center in 1999, there has been an increased usage of methadone within the institution. This study was designed to assess the effect of increased methadone usage on the overall cost of opioid utilization. METHODS: We evaluated the inpatient usage patterns for methadone (oral, SQ, and IV), transdermal fentanyl (TDF), and sustained release oxycodone (SRO) and morphine (SRM). Using the pharmacy database, for the month of October in each year from 1999-2004, the following data was collected: total milligrams used per day by product, conversion to morphine equivalent daily dose (MEDD) used by product, average wholesale price (AWP), number of unique patients by product, total days of product use, and total number of inpatient days (INPD). A total of 12,625 unique drug doses were included in the final database RESULTS: The number of unique patients receiving opioids increased for all study drugs. The usage of methadone in MEDD increased 400% from 1999 to 2004. Using AWP per patient day treated, TDF was $9.43, SRO was $3.63, methadone was $2.38, and SRM was $1.24. In total usage, methadone provided the largest MEDD (mg/day) coverage, up to 9 times the amount of TDF. Since 2000, methadone has contributed more MEDD as a percentage than the other 3 agents combined, while the methadone MEDD cost contribution has never been more than 10%. The mean for the cost of 1 mg of MEDD per patient day was $0.02 for methadone, $0.02 for SRO, $0.11 for SRM, and $0.216 for TDF. CONCLUSION: Usage of methadone has increased. The MEDD contribution of methadone surpasses other long acting opioids in our inpatient population. The non-annualized total cost per MEDD mg for all products combined has remained stable at $0.05, but cost per patient treated increased by $0.77 per (INPD). Analysis continues.