I'm not sure GPs know much about it because I'm sure they would use it more often...I only found out about it at A&E..after having a boatload of gas and air and a shot of morphine. A&E doc asked what I was taking and I told her I was on codeine but they werent working well and I told her I was taking up to 300mg at a time (not on the advise of my doc mind...just to stop me having another trip to hospital through the pain) and she said I must have a really high tolerance after she told me off for taking so much. Then she mentioned nefopam and sent a note to my doc, who perscribed it the next day.
It doesnt work too well when the pains severe though, but it works sometimes.
Theres something called fenatryl that could be tried before injections and that too. I've never had it (doc refuses, says its too strong
) but apparently its like a time release patch that you stick on your arm like one of those that stop you smoking. No idea how it actually works but loads of people swear by it
They tried me on tramadol too, though I didnt know it was classed as an opiate. Absolutely useless stuff. Had to take high doses of that too but it did nothing at all for the pain really, just made me feel slightly like I was on speed, then I found out it causes seizures :S