A long post about pain, and the relative strengths of painkillers.

If you can help please read and comment.


I am trying to work out the relative strengths of the painkillers I've been prescribed, to see if they are strong enough and to work out what to do next.

I once got good pain relief, that was from buprenorphine patches. I needed a minimum of 20μg buprenorphine per hour to make the pain tolerable during the day (and to reduce it at night). When I went up to 35 μg it also removed the pain overnight. However I had to stop the patches because they made me into a zombie, and the plasters scarred my arm.

Still, it means I know what I need. I'm going to consider what pain relief I need over 12 hours, because it's different at night.

This word document, which can be downloaded from here states that 1mg buprenorphine is equivalent to 80mg morphine. (It also gives the equivalents for other drugs, see below.)

During the day I need 240μg, or 0.24mg, buprenorphine over 12 hours. 1mg buprenorphine is equivalent to 80mg morphine, so over 12 hours I need the equivalent of 19.2mg morphine for my pain relief. Let’s call it 20mg over 12 hours. Now, let’s see if what I’m prescribed comes close to that.

During the day I take 2x30mg dihydrocodeine every 6 hours, so that’s 120mg DHC in 12 hours.

1mg DHC is equivalent to 0.1mg morphine, so I’m getting the equivalent of 12mg morphine. No wonder I’m in pain, that’s short of the 20mg needed!

However I’m prescribed 10mg oxycodone for breakthrough pain. This is equivalent to 13-20mg morphine – sounds like I need to start taking it! It might even be strong enough on its own, so I could swap to that from the DHC, perhaps. I haven't tried the oxycodone yet though.

At night I take 50mg tapentadol, slow release over 12 hours. My night time pain is stronger than in the day and I need more to nail it, the 35μg patches worked well at night but that’s equivalent to 33.6mg morphine.

50mg tapentadol is equivalent to 13.5-20mg morphine so it should be marginally stronger than the DHC I’ve been taking but I was still in pain. Last night it felt like nothing and I had to top up with DHC in order to get to sleep. I was miserable in the small hours, burning pain spreading up my thighs from both knees.

I wonder if I could double up the tapentadol? So far it hasn’t given me any side effects – nor do the DHC, so I’m happy to take them.

Next stop is to try the oxycodone for breakthrough pain, maybe that’s what I should have taken last night, but the DHC was by the bed.

The oxycodone dose seems to be equivalent to the tapentadol dose except the oxycodone is to be taken every 4-6 hours and the tapentadol is expected to last 12 hours when my pain is at its worst! This seems back to front to me.

Also, curiously the oxycodone leaflet basically says "if you take alcohol and it makes you tired, you ought to stop" whereas the tapentadol leaflet practically screams "Do not drink alcohol, ever!"

I’m a little wary of the oxycodone as it’s stronger and supposedly has more side effects, but I think I need it...

Are my calculations correct? Do you take either tapentadol or oxycodone, with good results? Experiences of either drug would be very useful. And finally, those in the know, what dose do you think I should be on?

Any advice welcome.