Hello dr. i have a question about vyvanse (lisdexamfetamine). is there anything i can do to rid of the amphetamine in my system/urine faster? drinks? food? exercise?

No: none of those things actually have any significant effect on how most drugs are excreted from the body. Large amounts of liquid may dilute urine enough to cause a chemical to fall below the "detection threshhold" of the test, but such dilute urine itself will be detected and is considered a "failed" urine. If it's prescribed, it should not be a problem. If not, getting caught least of worries.