potentiating codeine with grapefruit juice

[Im_Soooooo_High]

quick question does grapefruit juice potentate codeine ?

i know it potentiats most opiates but some people say it works for codiene and some say it dosent.

 

[Antagonistix]

Id like an answer for this too. Lots of contradictory posts on it.

Someone?

 

[effie]

White grapefruit juice predominantly inhibits one of your CYP-450 enzymes (CYP-34A) which metabolises several opioids (fentanyl, tramadol, hydrocodone) but not codeine. It also metabolises many benzos inc diazepam, alprazolam, clonazepam, temazepam, triazolam etc. There's no point taking it with codeine; in fact, there is no point taking any enzyme inhibitor alongside codeine. Codeine is a prodrug (it is not active itself but needs to be metabolised into morphine and codeine-6-glucuronide to exert it's affects) so inhibiting it's metabolism would be counter-productive.. same for tramadol. Drugs such as hydrocodone I am not sure about; they are active themselves, so inhibiting their metabolism will boost plasma concentrations, but it also have active metabolites (hydromorphone) and inhibiting metabolism will reduce the concentration of these.

GFJ works best for potentiating benzos.

There is a handy CYP-450 interactions chart here (-2D6 and -34A are the ones to focus on) - it doesn't list every substrate/inhibitor/inducer but it is a good place to start

 

[Pilll_head]

Grapefruit juice primarily inhibits CYP3A4, which metabolizes opiates to an inactive metabolite. CYP2D6 is what is responsible for metabolism of codeine to morphine. Drinking grapefruit juice will slow the CYP3A4 metabolism (to the inactive metabolite) and lengthen the buzz. I recently switched to Tagamet (600 mg, 1 h before) which is also a CYP3A4 inhibitor instead of grapefruit juice because the GFJ tastes so horrible. However, I wouldn't do this with codeine because Tagamet inhibits CYP2D6 as well so you would get no pain relief or buzz. If you are taking oxy or hydrocodone, those are active by themself so enzyme inhibitors won't prevent buzz or pain relief

 

[laCster]

awesome post effie!!!

the best grapefruit juice to use is 100% pure or in other words, not from concentrate. white grapefruit juice is the best, but when talking about GFJ, white means exceedingly light pink. simply grapefruit juice is the best brand IMO, but eating a fresh grapefruit and drinking residual juices provides more furanocoumarins thus increasing potency

on the surface, GFJ seems like the best potentiator for codeine because it does not inhibit 2D6 which is the enzyme that converts codeine into morphine. however, research shows that its main glucuronidation metabolites accounts for almost all of its opiate effects.

tagamet inhibits 3A4 stronger than GFJ, and it is more reliable and consistent than GFJ because the amount of furanocoumarins highly varies from batch to batch. prolonging the metabolization of codeine into inactive metabolites allows for more codeine molecules to be glucuronized thus increasing and prolonging the effects of codeine.