Inclusion Criteria:

- Pain due to cancer or its treatment; Controlled baseline pain; episodes of
predictable, treatment related pain every day that are 4"/10" in severity or greater,
last 10 minutes or longer, or episodes of breakthrough pain not related to cancer
treatment, and are responsive to short acting oral opioids such as morphine or
hydromorphone; are able to hold a volume of 1.0cc of water under tongue for a
2-minute period; are able to provide written informed consent; are able to fill out
the study forms, and are inpatients

Exclusion Criteria:

- Severe underlying respiratory disease such that the investigator is wary about the
risk of respiratory failure from modest doses od opioid; prior sensitivity to
methadone; currently are being administered methadone; are clinically unstable or
have a life expectancy of less than one month making completion of the trial
unlikely; and if they do not understand English sufficiently to provide written
informed consent.