Sorry - this will just be quick as not really got any energy to think much.
The two molecules for codeine and dihydrocodiene are very similar - but the dihydrocodine has two (di) hydrogen (hydro) atoms on it extra to codeine!
Potency wise, dihydrocodeine is probably stronger at equivalent weights. This would be for both pain relief and side-effects. They are both weak opioids and so only really for mild-moderate pain and you get lots of constipation with them.
In theory they are both very similar. But in patients then there can be totally different. i.e. pain relief may be none or great and side-effects can be little or lots and when you swap to the other one it could be pot luck again (as with every other pain killer).
So lil-miffy - I would definitely tell your GP that you found dihydrocodiene is better for your pain - he should also have received something from the hospital saying you had it. (In theory it is a more potent pain killer and he should realise that). I would also suggest you push for a referal to a pain management course or specialist - that way you can show you are willing to learn other ways of dealing with your pain and not just after opiates. It is going to be difficult for you to find pain killers that don't interfer with your other medication so you need to look down the route of as many other pain relieving options as possible.
Nonya - you are right caffiene can enhance the absorption and speed up the benifit of opioids and paracetamol and is the reason it is added to many over-the-counter pain killers. I am not sure which brands of codeine and dihydrocodiene may or maynot contain it - you would have to check each ingredient list. The modified release preparations (MR) can be useful to provide a more level effect of pain relief and side-effects during the day and night. Also - i couldn't have worded the bowel management as well as you
Benign Joint Familial Hypermobility Syndrome (BJFHS) - Confirmed Prof Bird April 2008
I am a Pharmacist and I will give my opinion on these boards. However, always ask your own health professionals for your individual circumstance.