Why people take painkillers and how opioid painkillers work


Medicines are an important factor in helping to treat persistent pain. They are usually prescribed and therefore have a great deal of research to support their use in treating people with pain. Many people with long term persistent pain conditions are prescribed medicines for pain.

Medicines are used safely by millions of people in the UK every day but medicines can be potentially dangerous. It is therefore very important to read the instructions and not take more than prescribed.

The following medicines are commonly used to help manage pain. 

  • Paracetamol, this is really good for usually mild musculoskeletal pain and anti inflammatory effects. It is mostly given as tablets. 
  • Non Steroidal Anti-Inflammatory Drugs (NSAIDS), such as ibuprofen, diclofenac, celecoxib, naproxen. These are used for inflammation such as sprains or soft tissue injury and some longer term conditions like arthritis. 
  • Antidepressants such as amitriptyline, duloxetine and nortriptyline. These are mostly used to treat nerve pain. These medicines are not licensed for use in persistent pain conditions but can be useful in some individual cases.
  • Anti-epileptics such as gabapentin and pregabalin. These are used to treat nerve pain. These can lead to dependence and are a controlled medicine.
  • Opioids such as tramadol, codeine, morphine and oxycodone. These are used to treat moderate to severe pain. These medicines are not effective in persistent pain conditions for most patients (PHE 2019). Opioids are narcotics and block the feelings of pain. They work by activating opioid receptors on nerve cells.Opioids attach to proteins called opioid receptors on nerve cells in the brain, spinal cord, gut, and other parts of the body. When this happens, the opioids block pain messages sent from the body through the spinal cord to the brain (ascending pathway) as well as mediating inflammation (descending pathway). 

All of these medicines would ideally be used for the least amount of time for the disease to be treated or managed. Long term use of any of these medicines can potentially lead to harmful effects and so prescribing for longer periods should consider a benefits versus risk discussion with your prescriber and the medicine stopped if there is little or no effect or if their use increases risk of harm to the person. This can seem unfair but non-medical and self-management approaches to pain conditions can have better outcomes which are sustainable without the risk of adverse effects or long term harm. 

The term ‘painkiller’ is a misnomer because pain medicines do not extinguish persistent pain. So if pain medicines do not provide 100% pain relief, what percentage of relief is good enough? The evidence suggests that those getting good pain relief describe a reduction of between 10- 40%.

Most people tend to have one of the following experiences:

  1. no benefit at all and maybe experience side effects
  2. some benefit but no side effects (takes the edge off)
  3. some benefit with side effects but these side effects are tolerated
  4. good benefit (with/without side effects)

The use of strong pain medicines has reached the news over the past ten years particularly as fears increase about over prescribing, over use by patients, problems with stopping and in some cases overdoses/deaths.

Strong pain medicines are not indicated for long term use in persistent pain except in a very small number of cases.