Painkillers
I really don't recommend painkillers as a way of controlling back pain - for the simple reason that they don't work. I know this from experience...
When I first started getting back pain, the pain would wake me at about 4am every morning. My initial response was to take some ibuprofen - and arrange an appointment with my doctor. Unfortunately, my doctor didn't tell me anything I didn't know - he basically said that the spine was very complex and nobody really knew how it worked, and prescribed me some stronger, slow-release ibuprofen.
(To be fair to him he did later send me for testing in case I had ankylosing spondylitis, but the tests were negative, thankfully.)
And so I remained on painkillers for a couple of years, getting repeat prescriptions as needed. But it never solved the problem. And worse, it didn't encourage me to solve my back pain problem permanently. Instead I just started on the slippery slope towards dependency.
Eventually I decided enough was enough. There were enough scares in
the media about long-term use of painkillers that I decided to wean
myself off the drugs and sort my back out once and for all. I've tried
all sorts of things (as I describe on this site), but I'm happy to
report that I don't now routinely need painkillers. (I do occasionally
take ibuprofen if needed, but only as a last resort.)

Long term effects
I think the thing that really drove me away from painkillers were their reported long-term effects. Reading around, the most frequentyly reported side effect of ibuprofen and other NSAIDs (nonsteroidal anti-inflammatory drugs) is gastrointestinal bleeding. There may be other effects, including kidney failure. You are apparently at greater risk of these if you take high doses of these drugs over a long period of time. (However, I'm not sure exactly what a "high" dose is - or a "long" period, for that matter.)
From what I can tell (and as I've said before, I'm not an expert!) medical science seems to be undecided about the long-term effects of ibuprofen and other NSAIDs. In writing this I've done a bit of research on the Internet but found it frustratingly inconclusive. On some sites I found a scary list of horror stories (bleeding, kidney failure as above), and yet my doctor has told me (when I asked about the long term effects of taking ibuprofen) that the scare stories were mostly media overreaction and hysteria - and that there are few proven long-term effects.
So who do I trust? And what do I do?
Personally, I've adopted what I regard is a common sense approach. Seeing as we didn't evolve to be dependent on pain killers, my personal preference is not to take them unless I really, really need to.
As always you should do your own research - it's your body and if you have concerns start with your doctor.
Your stories about painkillers
If you have any stories or comments (or even tips) about using painkillers in response to your back pain, please share them with me and I'll add them to this site. Click here to tell me your story.
