What is "hydroxybupropion"

Hydroxybupropion (code name BW 306U), or 6-hydroxybupropion, is the major active metabolite of the antidepressant and smoking cessation drug bupropion. It is formed from bupropion by the liver enzyme CYP2B6 during first-pass metabolism. With oral bupropion treatment, hydroxybupropion is present in plasma at area under the curve concentrations that are as many as 16–20 times greater than those of bupropion itself, demonstrating extensive conversion of bupropion into hydroxybupropion in humans. As such, hydroxybupropion is likely to play a very important role in the effects of oral bupropion, which could accurately be thought of as functioning largely as a prodrug to hydroxybupropion.

Compared to bupropion, hydroxybupropion is similar in its potency as a norepinephrine reuptake inhibitor ( IC = 1.7 µM) (and likely also acts as a norepinephrine releasing agent, similarly to bupropion), but is substantially weaker as a dopamine reuptake inhibitor (IC = >10 µM). Like bupropion, hydroxybupropion is also a non-competitive antagonist of nACh receptors, such as αβ and αβ, but is even more potent in comparison.