I started taking Vyvanse four days ago for ADHD. Day 1 I took 20 mg, days 2 and 3 I took 40 mg. (no side effects) Today I took 60mg bad side effects- diarrhea, nausea, racing heart, mild shortness of breath, jitters. I also take Pristiq for depression 100 mg, I have been taking it for many years. I forgot to take Pristiq today. Can I lower from 60 - 40 mg tomorrow? Is it safe? In addition, my doctor wants me to stop taking the Vyvanse after tomorrow and try Adderall separately to see what dosage, if any of that medication is therapeutic. Thoughts??? Advice???