Bupropion ER 150mg is an extended-release formulation used primarily to treat major depressive disorder and aid smoking cessation. Like other bupropion forms, it works by inhibiting the reuptake of norepinephrine and dopamine, enhancing mood and reducing nicotine cravings. The ER (extended-release) form allows for once-daily dosing, maintaining more stable blood levels of the drug for better efficacy and convenience. It is often preferred due to its consistent therapeutic effects and reduced risk of side effects compared to immediate-release formulations.