For this reason, I take the generic bupropion SR
(also it is cheaper for me). When I started, I was taking the SR
150mg only in the morning, then after 4 weeks the dr. had me take it 150mg in the morning and 150mg in the evening. I could definitely tell the difference with the twice daily regimen, but for me it took several weeks to get the full effects; although, it helped with mild ED right away. I'm not a Dr., but I think the generic SR is fine.