codeine/morphine allergy question

[Celtic Cthulu]

I think i finally found a question the search engine couldn't answer. So i've read codeine is metabolised into a small amount of morphine by the liver. Does this mean that if you aren't allergic to codeine, you also wouldn't be allergic to morphine? I don't mean the histamine reaction but a true allergic reaction. Any input on this would be greatly appreciated! mods please feel free to move this wherever it should go!

 

[nAON]

In theory, yes. In practice though, because the metabolism yields very small amounts of morphine and it does so slowly over a period of time, it might be difficult to discern between an allergic reaction to morphine and just the normal histamine response. If you're worried about morphine allergies you should get it tested properly.

 

[Celtic Cthulu]

I've actually had morphine before, years ago. They were 30mg IR tablets. They were really mild, not sure if it was cause of the shitty oral BA or because they'd expired. This is just something i've been pondering for a while. Thanks for the input!