Different painkillers have their own, individual way of operating, but, in essence, they all prevent pain signals from reaching the brain. Aspirin and ibuprofen, for example, block the formation of chemicals (known as prostaglandins) that stimulate the pain receptors in the body and without this, the pain signal is not produced in the first place.
Local anaesthetics, such as Novocaine, provide pain relief by preventing the transmission of the pain signal, from the receptors to the brain the signal is produced, but it does not go anywhere.
Finally, morphine and other opiate drugs mimic the effects of naturally occurring brain chemicals (endorphins, for example) that alter our perception of pain, making it appear less noxious; in essence, the signal gets through to the brain, but it is interpreted differently.
By their very nature, analgesics only work for a short period of time. Hence, to manage long term (or chronic) back pain, they need to be taken frequently. As a result, patients often develop a tolerance for the drug in question (an effect known as down regulation), and this leads them to seek stronger, or more frequent medication.
Side effects and drug dependency are also relatively common. For example, in a study conducted at the University of Toronto into the effects of long-term codeine use, 40% of patients were found to exhibit drug dependence, as defined by DSM-IV criteria (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition™). 67% sought help for mental health problems, most commonly depression. They concluded that ‘long-term codeine use is strongly associated with dependence’, and that ‘depression and depressive symptoms are common’.
Source: Journal of Clinical Psychopharmacology 19: 373-376 (1999); Dept. of Pharmacology, University of Toronto.
Painkillers are the most popular treatment for the symptoms of back pain: they are readily available, easily consumed and relatively cheap; doctors are also likely to prescribe them.
However, they only work for short periods of time – to manage long-term back pain they must be taken frequently. Tolerance, drug dependency and side effects are relatively common. They do not treat the causes of back pain.
Approximately: £15 for 100 tablets (200mg ibuprofen + 12.8mg codeine phosphate).