Hydroxy bupropion

XL is best dosed once a day, whereas SR is best dosed twice daily, and immediate release is best dosed 3 times daily Dosing higher than 450 mg/day (400 mg/day SR) increases seizure risk Patients who do not respond to 450 mg/day should discontinue use or get blood levels of bupropion and its major active metabolite 6-hydroxy-bupropion If levels of parent drug and active metabolite are low despite dosing at... 

FIGURE 12.11 Metabolism of bupropion by CYP2B6 to hydroxy-bupropion and the structure of the stable iso tope-labeled internal standard [ H ]hydroxybupropion. 

Hydroxy bupropion Sepracor Phenyl aminoketone (R-isomer of bupropion) Noradrenaline reuptake inhibitor... 

At the other extreme, trazodone, nefazodone, and venlafaxine have short half-lives (about 3 to 6 hours), as does the active 4-hydroxy metabolite of venlafaxine (half-hfe of about 11 hours). The half-life of bupropion is about 14 hours. Owing to rapid aromatic hydroxylation, the half-hfe of nefazodone is very short (about 3 hours). The shorter durahon of action of these agents usually imphes the need for mulhple daily doses. Some short-achng antidepressants have been prepared in slow-release preparations (notably bupropion and venlafaxine), to ahow less frequent dosing and potentiahy to temper side effect related to agitation and GI disturbance. 

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