Heyas, I have a few questions regarding these enzymes and some of the terminology. Most of my queries/info is from wiki to keep it reasonably simple and less time consuming
CYP2D6 - a substrate for things like codeine, tramadol, venlafaxine (effexor - SNRI), DXM
Ok so a substrate of an enzyme means it is partially or wholey responsible for metabolising these substances and hence making them 'work'? If one was on say venlafaxine (and had a normal genotype regarding this enzyme) does this mean that doses of say codeine or DXM would be much less effective because CYP2D6 is also busy metabolising the efexor? (particularly if it is time release XR)
In addition it seems that much SSRIs are both substrates and inhibitors of CYP2D6 (and from reading on here codeine is also). Inhibitor - binds to the CYP2D6 enzyme and decreases it's effectiveness? But codeine is not in the inhibitor list of CYP2D6 or CYP3A4 enzymes, and I have read on here that redosing it doesnt work because it is itself an inhibitor of its metaboliser. wtf?
So to make a drug more effective we want an inducer of the relevant enzyme right? Or do we want an inhibitor to make the drugs effect last longer. I need some clarity on these points pls eg grapefruit juice is an inhibitor of CYP3A4 but is reccomended as a potentiator for say codeine, which is metabolised by both CYP3A4 & CYP2D6.......
CYP3A4 seems to be a substrate of heaps of gear like benzos, antipsychotics, SSRIs, DXM, codeine, fentanyl, barbituates, zopiclone etc. So arent we looking for inducers of CYP3A4 to increase the metabolic rates for these drugs? But from reading on here the grapefruit juice and cimetidine which are inhibitors of CYP3A4 potentiate codeine/opiates??
Lastly the enzyme that metabolises zolpidem (ambien/stilnox) is apparently CYP34A, now is that definately a different enzyme than CYP3A4!! Anyone know any inducers/inhibitors of CYP34A?
Thanx for reading this just need some enzyme action/terminology straightening for interests sake and to keep my medications working and also the recreactional ones
cheers, mcwally
CYP2D6 - a substrate for things like codeine, tramadol, venlafaxine (effexor - SNRI), DXM
Ok so a substrate of an enzyme means it is partially or wholey responsible for metabolising these substances and hence making them 'work'? If one was on say venlafaxine (and had a normal genotype regarding this enzyme) does this mean that doses of say codeine or DXM would be much less effective because CYP2D6 is also busy metabolising the efexor? (particularly if it is time release XR)
In addition it seems that much SSRIs are both substrates and inhibitors of CYP2D6 (and from reading on here codeine is also). Inhibitor - binds to the CYP2D6 enzyme and decreases it's effectiveness? But codeine is not in the inhibitor list of CYP2D6 or CYP3A4 enzymes, and I have read on here that redosing it doesnt work because it is itself an inhibitor of its metaboliser. wtf?
So to make a drug more effective we want an inducer of the relevant enzyme right? Or do we want an inhibitor to make the drugs effect last longer. I need some clarity on these points pls eg grapefruit juice is an inhibitor of CYP3A4 but is reccomended as a potentiator for say codeine, which is metabolised by both CYP3A4 & CYP2D6.......
CYP3A4 seems to be a substrate of heaps of gear like benzos, antipsychotics, SSRIs, DXM, codeine, fentanyl, barbituates, zopiclone etc. So arent we looking for inducers of CYP3A4 to increase the metabolic rates for these drugs? But from reading on here the grapefruit juice and cimetidine which are inhibitors of CYP3A4 potentiate codeine/opiates??
Lastly the enzyme that metabolises zolpidem (ambien/stilnox) is apparently CYP34A, now is that definately a different enzyme than CYP3A4!! Anyone know any inducers/inhibitors of CYP34A?
Thanx for reading this just need some enzyme action/terminology straightening for interests sake and to keep my medications working and also the recreactional ones
cheers, mcwally