A Study of Safety and Effectiveness of Ultracet in Patients With Chronic Cancer Pain

Inclusion Criteria: * Participants whose pain has reached a stage now requiring treatment with a weak opioid, according to the opinion of treating physician * Participants who have received a regular weak opioid, for at least 48 hours and at a dosage appropriate for their pain at that time * Participants with a histologically, radiologically or hematologically confirmed malignancy; whose pain is judged by the investigator to be caused by the malignancy Exclusion Criteria: * Participants who have already received regular treatment with a strong opioid for their cancer pain. This should not exceed more than 3 doses of a strong immediate release opiod in last 7 days, and none in last 24 hours * Participants with significant abnormalities in hepatic or renal function which would in the opinion of the investigator, prevent the participants involvement in the study * Participants with a history of allergy or hypersensitivity to tramadol or acetaminophen * Participants who, at entry have treatments planned which may alter abruptly, the degree or nature of pain experienced (eg radiotherapy, neurological techniques surgery) * Participants with a history of abuse of opioid analgesics prior to their diagnosis of cancer