A Randomised Controlled Trial Investigating Possible Additive Analgesic Effects of Paracetamol in Palliative Patients using Low-dose Strong Opioids

All patients will receive five days of paracetamol (two 500mg tablets per oral four times a day) and five days of an identical appearing placebo. The primary outcome, pain, will be assessed subjectively by patients completing a daily diary ( of numerical ratings of pain on an 11 point Likert-type scale with values ranging from 0 (none) to 10 (unbearable), for each of the 5 days of both treatments. In addition, the numbers of breakthrough medications used each day will be recorded. Secondary outcomes of subjective ratings of nausea and vomiting, cognitive impairment (drowsiness and unclear thinking), constipation and overall feeling of well-being will also be assessed using 11 point Likert-type scales. A one day washout period dictates that only data from the last four days of each treatment arm will be analysed to exclude the influence of possible carryover effects. At the completion of the study patients will be asked to rank their global satisfaction with the two treatments. They will be given the option of continuing with paracetamol and asked the reason for their choice.