Pain Killers and types of pain

Factual Questions
1

Hello Everyone,
Another mystery that I can’t figure out, hopefully someone here has a bit of medical knowledge they can share. This is actually a two part question.

1: Due to sevre chronic pain I take 60mg of morphine everyday. The pain I am treating is due to a back injury which required a fusion of my spine from L3 to S1. To my dismay I have discovered that while my back is now stable I am left with a lifetime of unbelivable pain that the doctors can’t seem to determine the cause of. So the only option is opiods to manage. On top of the morphine I take Percocets for breakthru pain. The meds work well on the back pain, however tonight I have a toothache and I can’t understand how I can have pain in my tooth even though I am on these supposedly strong painkillers. Thinking back some years ago when I had a previous toothache, I took Tylenol and it wiped out the tooth pain incredibly well. Why is it in my case morphine seems ineffective, but something as weak as an OTC pain reliever will work? (on the oposite side Tylenol is totally ineffective at treating the back pain)

2: Due to the years of use of morphine, fentynal, vicodin, percocets and a few others I don’t remember I have develped quite a tolerance to pain meds. I will soon have to go to the dentist to have this tooth worked on. I am a bit nervous because my last visit to the dentist was horrible due to the fact that nothing he seemed to do would render my tooth numb. He shot me at least 6 or 7 times with novicane and even had me on nitrous. Zero effect at all from either. He could only conclude that my long term use of opiods had built my tolerance up so high that he couldn’t numb me with the novicane and nitrous. If this is the case how will I ever be able to get work done on my teeth? Is sedation the only option or is there a protocol to deal with people who don’t react to standard procedures? I do realize that this is a question best answered by my dentist. It would be helpful however that when I do talk to him I have a bit of knowledge so I can understand what options he might suggest.

Thanks!

2

I think opiates work at nerve roots, where nerve bundles enter the spinal canal. They don’t work well on nerves that reach the brain without passing through these junctions, such as facial nerves. This is something I think I heard a few years ago about trigeminal (sp?) neuralgia.