Why has specifically morphine stopped working for me?

[I<3myopiates]

I've been taking opiates almost daily for years. The only kind that has never really worked for me since the beginning is Tylenol w/ codeine. All other opiates have always done the job in pretty small doses. For example, two lortab 10mg a time every 4 to 6 hours is perfectly fine for me, so basically 2 of any type of opiate in this equal dose range. Or I can take one 80mg oxy and be good for hours. And I have never had to take more to get to the same place. But the last few years, with morphine, the only way I will feel ANYTHING is if I take atleast a 100 mg pill. Why is this the only one that I have to take more of to feel any relief when it's just as potent or strong as the other stuff? It drives me nuts, because sometimes morphine is all I can find. Wtf?

 

[MikeOekiM]

tolerance. also morphine's oral bioavailability is rly low compared to oxycodone's

 

[spacejunk]

Also, varsiations in individuals' liver enzymes.
Some people don't metabolise codeine well.

 

[alasdairm]

support -> od

alasdair

 

[burn out]

because mother nature intended morphine to be used in conjunction with the other alkaloids she placed in the opium poppy, not extracted out and used on its own. the other alkaloids slow down the breakdown of morphine in the body and make it much more effective.

 

[Slow_Mobius]

I mean, oxycodone is about 1.5x stronger than morphine, so of course 80mg oxycodone will be stronger than 100 mg morphine.

Also some people just respond better to different drugs within the same class. Very common.

 

[kleinerkiffer]

Oral bioavailability of morphine is pretty bad and as spacejunk said variations in individuals' liver enzymes

Regarding codeine, it's a prodrug and needs to be metabolized by CYP2D6 and many people have a gene mutation making them slow metabolizers, so I guess you're one of them