Paracetamol for cancer pain
There is no evidence to show that paracetamol is useful in treating people with cancer pain, either alone or combined with a morphine-like drug. Nor is there evidence to disprove that it is useful. There are no good studies evaluating paracetamol for management of cancer pain.
One person in two or three who gets cancer will suffer from pain that becomes moderate or severe in intensity. The pain tends to get worse as the cancer progresses. In 1986, the World Health Organization recommended taking morphine-like drugs (opioids) for moderate to severe pain from cancer, and non-opioid drugs like paracetamol, alone for mild to moderate pain, or alongside opioids in people with moderate to severe pain.
In this review we set out to examine all the evidence on how well paracetamol (alone or with morphine-like drugs) worked in adults and children with cancer pain. We also wanted to know how many people had side effects, and how severe those side effects were, for example, whether they caused people to stop taking their medicines.
In March 2017, we found three studies with 122 participants. All compared paracetamol plus opioid with the same dose of opioid alone. The studies were small, and were of poor quality. They used different study designs and different ways of showing their pain results. Outcomes of importance to people with cancer pain were not reported.
We found no evidence that taking paracetamol alone made any difference to the level of pain experienced. We found no evidence that taking paracetamol together with a morphine-like drug was better than the morphine-like drug alone. Paracetamol did not appear to improve quality of life. No conclusions could be reached about side effects. The amount of information and the differences in how studies were reported meant that no conclusions could be made.
Quality of the evidence
The quality of the evidence was very low. Very low-quality evidence means that we are very uncertain about the impact of paracetamol for treating cancer pain. We do not know whether using paracetamol alone, or in combination with an opioid such as codeine or morphine, is worthwhile.