Can u take adderall (dextroamphetamine and racemic amphetamine) and than diazepam?

Not a great idea: It would require unusual, if not exceptional, circumstances for these two meds to be prescribed in conjunction with one another. They do not have precisely opposite effects on the brain but close enough so that their combination is generally not a good idea. Check with your prescriber. Sometimes street versions are used as uppers and downers. This, for certain, you should avoid.