It's my 2nd day of vyvanse (lisdexamfetamine) 20 mg today.have a job interview at 3 pm. i sometimes take 5 mg of valium before stressful situations like this; is it ok?

Prescriber: Whether Valium is a useful medicine for you, under what circumstances, in combination with what other medicines -- this needs to be decided by you and your prescriber.

Yes.. but: be sure you are taking as directed by your doctor and know how Valium 5 mg will effect you so you don't feel sleepy, etc before interview. Relaxation techniques are also good to help with stress reduction: http://www.mayoclinic.org/healthy-lifestyle/stress-management/in-depth/relaxation-technique/art-20045368