This study is designed to evaluate the safety and effectiveness of using a combination of two different medications (extended release naltrexone and bupropion) compared to matching placebo (an inactive substance) in the treatment of methamphetamine use disorder. Participants will undergo screening, and if eligible, will receive study medications along with brief medication management for twelve weeks, with follow up visits at weeks 14 and 16. The total study duration is around 19 weeks.