Is it safe to take a 70mg Adderall (dextroamphetamine and racemic amphetamine) pill?

Wha? . The biggest dosed pill of Adderall is 30 mg. You must mean vyvanse (lisdexamfetamine) which goes up to 70 mg. The dose of stimulant is determined by the response of the patient & the absence of side effects. Your doctor is best positioned to help decide which dose is best for you. As long as you tolerate the medication, the actual dose is unimportant.