Bupropion is presumed to be a dopamine-norepinephrine reuptake inhibitor and is an effective antidepressant. It is available as three oral formulations: (i) bupropion immediate release (IR) [Wellbutrin] administered three times daily; (ii) bupropion sustained release (SR) [Wellbutrin SR] administered twice daily; and (iii) bupropion extended/modified release (XR) [Wellbutrin XL /Wellbutrin XR ] administered once daily. All three formulations are bioequivalent in terms of systemic exposure to bupropion.

Oral three-times-daily bupropion IR was effective and generally well tolerated in the treatment of major depressive disorder (MDD). It was as efficacious and as well tolerated as some tricyclic antidepressants (TCAs) and the selective serotonin reuptake inhibitor (SSRI) fluoxetine. Moreover, it was associated with less somnolence and weight gain than some TCAs. Twice-daily bupropion SR was also efficacious and generally well tolerated in the treatment of MDD. It was as effective as and had a generally similar tolerability profile to some SSRIs, but had the advantage of less somnolence and sexual dysfunction. (more…)

The most frequently used drugs are tricyclic antidepressants, which received their name from the organization of their chemical structures, in particular the systems consisting of two benzene rings joined to a central 7-membered ring with a dialkylaminoalkyl group connected to the central ring. Depending on the substituents on the terminal nitrogen atom in the amine-containing side chain, they in turn are subdivided into tertiary (imipramine, amitriptyline, trimipramine, doxepin) and secondary (desipramine, nortriptyline, protriptyline) amines. These classifications are very formal and are not based on the most essential structural variations of the examined drugs; however, they are accepted in pharmacology. (more…)