What to do if i had four 6 gm of vyvanse (lisdexamfetamine) at 9:00 am what can happen?

Do you mean....: ...4 of the 60mg capsules of Vyvanse (lisdexamfetamine)? There is no 6 gm capsule. Even so, 4 of the 60's is a pretty hefty dose and would NEVER be recommended. You will have trouble sleeping tonight and maybe even tomorrow night. Most seriously, high doses of stimulants can cause cardiac arrhythmias, heart attacks, and/or stroke, as well as precipitate a psychotic episode complete with hallucinations and delusions.