Bupropion can stay in a person's system for weeks. The effects of the medication are at it's highest at the seventh hour, as noted by AddictionBlog.
Bupropion, commercially sold as Wellbutrin among others, is used to treat depression. It is a nonnarcotic medication that does not have any addiction properties. It can only be traced in the bloodstream for a few days and on hair strands for 90 days. Wellbutrin is known to stay in the urine for up to a month. If a person is being tested for drugs, let the doctor know that this medication has been taken. Bupropion can produce a positive test result for amphetamines.