PHARMACOKINETIC PROFILES. Plots of the steady-state plasma concentrations of bupropion over a 24-hour period for the IR, SR, and XL formulations of bupropion are presented in Figure 1 (data on file, GlaxoSmithKline, Research Triangle Park, N.C.). Wellbutrin SR vs Wellbutrin XL. Feeling sad is natural for most people especially when there is good reason to be. Some things might not go the way we originally planned them. Bupropion is an antidepressant that you can purchase online if you don't intend to manage prescribeds and physicians, understanding your dosage and function of use. DESCRIPTION. WELLBUTRIN XL® (bupropion hydrochloride), an antidepressant of the aminoketone class, is chemically unrelated to tricyclic, tetracyclic, selective serotonin reuptake inhibitor, or other known antidepressant agents. Bupropion (Zyban) is an oral prescribed medicine that aids individuals to stop smoking cigarettes by decreasing hungers and removing some of the drawback signs. Compare Budeprion XL vs. Bupropion HCl, which is better for uses like: Depression, Anxiety and Withdrawal Symptoms. Compare head-to-head ratings, side effects, warnings, dosages, interactions and patient reviews. Effectiveness - Both Wellbutrin XL and Wellbutrin SR are preparations of the same antidepressant medication bupropion and are equally effective. Absorption - Absorption of the XL formulation is prolonged compared with the SR formulations - T (max) is approximately 5 hours vs approximately approximately 3 hours. I've been taking Bupropion XL for years. Due to recent changes in my insurance, I've had to switch pharmacies. My new pharmacist refilled my prescription with Bupropion HCL XL as opposed to the Bupropion XL I'm used to. Bupropion is the International Nonproprietary Name (INN) and British Approved Name (BAN) while bupropion hydrochloride is the United States Adopted Name (USAN). Amfebutamone was the former INN. Amfebutamone was the former INN. Compare Bupropion HCl vs. Wellbutrin SR, which is better for uses like: Depression, Anxiety and Smoking. Compare head-to-head ratings, side effects, warnings, dosages, interactions and patient reviews.