This information is for people who have long-term back pain. It tells you about painkillers, a treatment used for long-term back pain. It is based on the best and most up-to-date research.
Do they work?
If you have back pain, your doctor may recommend an over-the-counter painkiller such as paracetamol. We know painkillers help to reduce pain. However, there hasn't been much good research looking specifically at how well paracetamol works for long-term back pain. There's been more research on stronger painkillers, which do seem to help.
What are they?
Paracetamol is a commonly used painkiller. Your doctors may recommend you try it first to treat your back pain. You can buy paracetamol yourself from a pharmacy or supermarket.
If paracetamol doesn't work on its own, then your doctor may prescribe you paracetamol combined with a stronger painkiller called codeine (brand name Co-codamol). Adding codeine to paracetamol may reduce pain slightly better than paracetamol on its own, but you're more likely to get side effects from a combination of painkillers. 
Tramadol (brand names Zamadol, Zydol, Tramake) is another painkiller that might be used for back pain.
Codeine and tramadol belong to a group of drugs called narcotic analgesics (also called opioids). You need a prescription for most narcotic analgesics. However, you can buy paracetamol combined with a low dose of codeine from a pharmacist.
Narcotic analgesics come as tablets, liquids, suppositories (capsules that you put inside your bottom), and injections.
Usually, your doctor will only recommend that you take these drugs for a few weeks. This is because you can become dependent on them. If you take a narcotic analgesic for longer, your body gets used to it. When you stop taking it, you may get unpleasant side effects, called withdrawal symptoms.
Here are some examples of other narcotic analgesics (with brand names) that might be used to treat back pain:
Dihydrocodeine (DF118), or dihydrocodeine combined with paracetamol (Co-dydramol)
Non-steroidal anti-inflammatory drugs ( NSAIDs) are another type of painkiller that doctors often recommend for back pain. Ibuprofen is a well-known NSAID.
How can they help?
We know that paracetamol helps with pain. But there haven't been any good-quality studies looking at how well it works for long-term back pain.  
Studies on opioid painkillers haven't clearly shown that they help.  But overall, the research on these drugs isn't very good quality, so it's hard to say whether they help with long-term back pain or not. One study of an opioid called tramadol found that it reduced pain and helped people get back to their usual activities. 
How do they work?
Painkillers reduce pain by stopping pain signals getting to your brain.