half life

[danzman]

Hi, new to the forum.

I have a question for you pharmacological types out there…

When you use the term “half-life”, as it relates to an organisms ability to remove a chemical, does the given half-life incorporate all of the secondary metabolites associated with the chemical? As an example, the given half-life of morphine is 2-3 hours. Morphine is metabolized mostly in the liver by glucuronidation to various other morphine analogues (M3G, M6G…) Does this half life value incorporate the time needed to remove these chemical as well? Also, how does HL (half-life) relate to physiological activity? The HL for some benzodiazepines is in excess of 100 hours, yet their effects wear off in only a few hours. So by taking more of the drug one begins to saturate their system with inactive analogues. What is this potency rate called if not half-life?

 

thanks