Funding was terminated early due to slow recruitment.

National guidelines advocate the use of paracetamol in conjunction with strong opioids for cancer pain, despite a lack of evidence for its efficacy. Work is needed to examine the analgesic benefit of paracetamol in this large patient group. The investigators aim to establish if paracetamol in combination with strong opioids provides superior analgesia for cancer related pain over strong opioids alone.

Inclusion Criteria:

1. Age 16 years and over
2. Under palliative care/oncology service review
3. Diagnosis of incurable cancer
4. Clinician-predicted life expectancy >2 months
5. Anticipated to be clinically stable for duration of study involvement
6. Receiving daily regular strong opioids
7. Able to take study drug/placebo in its current form
8. Prescribed and taking paracetamol 1g four times a day
9. Average pain >3 and <9 in past 24 hours
10. Able to provide written informed consent
11. Able to complete necessary assessments required as part of the trial
12. Average NRS pain score stable (ie. maximum range of 1 point) for the three consecutive days prior to randomisation

Exclusion Criteria:

1. Pain which the clinician deems to be unstable
2. Clinically significant renal or liver disease
3. Weight less than 50kg
4. Those whose pain is expected to change during the course of the study as a result of oncological or other treatments
5. Co-enrolment in other drug trials
6. Known to be pregnant or breast-feeding at the time of recruitment
7. Previously enrolled in this study