Misc Phenobarbital, Does it weaken codeine, soma (prodrugs) or benzos?

[muie]

I've heard phenobarbital can make certain drugs much weaker. Currently I take clonazepam as well as the occasional codeine and soma (both are pro drugs). Although in theory the effects should be potentated since they're all downers but apparently pheno inhibits the same enzyme as st. johns wort which reduces the potency of benzos and opiates as well I believe.

I also heard pehno can make oxycodone and other stronger narcotics much weaker (which i may do from time to time).

So I'm wondering if anyone can shed any light on this subject.

Thanks

 

[klinklonfoonyak]

I thought its a barbiturate? If so it should potentiate drugs like that. Those drugs being benzodiazepines, opiates ( or is codeine a opioid?) And muscle relaxes like soma

 

[Znegative]

^No.
It is a (shitty) CNS depressant, but its also a CYP2D6 inducer, which will speed up the metabolism of certain drugs that are metabolized by Cytochrome P450, which can cause an early onset of withdrawal syndrome. However I also read somewhere that phenobarbital can heighten Codeine's ceiling effect which is interesting, but not really a reason to combine the two IMO.

 

[muie]

^^^ I too have recently read that phenobarbital potentates codeine, though there are conflicting reports. I just assumed that codeine needs to be converted first into morphine (via the same enzyme barbies compete for) thus weakaning the effect, though some people report potentation with just 50mg-90mg pheno.

Can you please elaborate further?

 

[muie]

BUMP

For the people that sustain barbiturates allow for more codeine to be metabolised via CYP2D6, what about Soma which too is a pro drug, would you apply the same laws?

On one hand you would think it's a much more intense effect since the'yre all sedatives which is natural to assume but on the other hand you only got 1 actual drug along with 2 pro drugs (which are competing for the same enzyme), which is why I'm posting here. Also I know of several drugs on the market that contain a mixture of phenobarbital/codeine, codeine/soma, butabital/codeine and so on so there has to be some potentation, rather than reduction in metabolism.

p.s. I'm not looking for a Doriden like potentator, but so far I've found Soma and Codeine a good combo though I'm not sure how the pharmakinetics work when a small barbiturate dose is added.