Your med is an amphetamine. I wonder if caffeine could do the job. Vyvanse is slow in initial action so it would need to be taken at least an hour before expected action from the active drug (dextroamphetamine). Then, its half life in the blood is 10 to 13 hours. The half life of caffeine is 5 to 7 hours.

The goal would be to give your brain a break from the stimulant effect of the drug.

Are you following a brain nutrition regimen like the vitamin regimen listed in the sticky ? It would be advisable since you are stressing your brain with the Vyvanse.