Painkillers such as paracetamol, ibuprofen, aspirin and opioids can do "more harm than good" and should not be prescribed to treat chronic pain, health officials have said.
Draft guidance from the UK's National Institute for Health and Care Excellence (Nice) said that there was "little or no evidence" the commonly used drugs made any difference to people's quality of life, pain or psychological distress.
But the draft guidance, published yesterday, said there was evidence they can cause harm, including addiction.
Chronic primary pain is a condition in itself which cannot be accounted for by another diagnosis or as a symptom of an underlying condition, Nice said.
It is characterised by significant emotional distress and functional disability with examples including chronic widespread pain and chronic musculoskeletal pain, it added.
Nice said an estimated third to half of the population may be affected by chronic pain while almost half of people with the condition have a diagnosis of depression and two-thirds are unable to work because of it.
The draft guidance said that people with the chronic pain should be offered supervised group exercise programmes, some types of psychological therapy, or acupuncture.
It also recommends that some antidepressants can be considered for people with chronic primary pain.
But it said that paracetamol, non-steroidal anti-inflammatory drugs such as aspirin and ibuprofen, benzodiazepines or opioids should not be offered because there was little or no evidence that they made any difference to people's quality of life, pain or psychological distress.
There was evidence that they can cause harm, including possible addiction, it added.
The draft guideline also said that antiepileptic drugs including local anaesthetics, ketamine and antipsychotics should not be offered to people to manage chronic pain because, again, there was little or no evidence that these treatments work but could have possible harms.