-induced insomnia is a supreme pain in the proverbial ass. Because the current preference for amphetamines on the market today is to make them as long-lasting as possible one can easily end up in a situation where they cannot sleep, need to be up for the new day, and are confronted with the choice of trying to induce sleep artificially or just pull through and re-dose to make up for the lack of sleep.
Canmedaa had this problem on both Adderall
and dextroamphetamine spansules (Vyvanse is just dextroamphetamine with an added molecule to make it inactive until its traversed the intestinal tract). When Canmedaa finally got to the point that she was binging on amphetamines to get through multiple days without sleep she decided to seek out the ol' tried-tested-and-true, very retro, version of dextroamphetamine, which is the instant-release tablet form sometimes called 'DextroStat". Dex IR is outdated and only really used for ADD/ADHD management of children too young to use extended-release forms of amphetamines on.
Dex IR lasts about four hours and has a rapid onset. More is not always better, and when it comes to how long a stimulant is going to work 8-11 hours seems a little like overkill to Canmedaa.
Because the OP is asking specifically about Vyvanse, which as Canmedaa said above is just Dextroamphetamine (Dexedrine) with a little extra something on it to make it last longer she would suggest that the OP try down-grading to either the regular dextroamphetamine spansules (appx. 8 hours of effect) or drop all the way down the ladder to the Instant-release format which gives far more control over when one would like to be under the influence and for how long.
It is not uncommon for Canmedaa to take between 10-20mg of Dex IR in the late evening and still get to sleep without artifical assistance by between 1-3am.
If the OP decides to try dropping down to previous footsteps in the evolution of Dextroamphetamine they will still be taking the same drug
, it just wont last as long. The prescribing physician can do the math to provide a dosage of a different format that is on par with whatever dosage of Vyvanse the OP is taking.