Xanax vs Valium my observation

[Keif' Richards]

A pro-drug is a great example of drugs that require little to no metabolism? Wouldnt morphine have been a better example?

I apologize if this is unclear, but I just mean to use Codeine as an example of the wide variability in terms of subjective and objective potency. The rule of thumb, if you will, is that Codeine (3-Methylmorphine) will ultimately be metabolized into Morphine at a rate of ~10%. Herein, lies the problem; not everybody fits into this category. I do not metabolize Codeine effectively. I have been overseas and extremely sick and Codeine was all that was available. I ended up doing a CWE of approximately 4,000mg Codeine. It essentially cured my restless legs and made me able to sleep.

I don't know what you call that, but I maybe metabolize Codeine at a rate of ~1%. I really don't know. It has an effect, but only in massive doses. Morphine is a great example of the opposite. Morphine is Morphine and there is a significantly lower variability in effects from person to person. It does not require metabolism to become active, so, there will be less of that variability.