Is it safe to take Vyvanse (lisdexamfetamine) 50mg and Dexedrine (dextroamphetamine) 5mg at 7:00am and Dexedrine (dextroamphetamine) 5mg at 2:00pm?

Can This Combination Be Taken Safely?

Yes, taking Vyvanse 50mg plus Dexedrine 5mg at 7:00am, followed by Dexedrine 5mg at 2:00pm is safe and clinically appropriate, as this totals 60mg of dextroamphetamine equivalent daily, which remains within established maximum dosing limits. 1, 2

Total Daily Amphetamine Dose Calculation

• Vyvanse 50mg converts to approximately 20mg of dextroamphetamine after enzymatic hydrolysis in the blood 3
• Adding the two 5mg Dexedrine doses yields a total of approximately 30mg dextroamphetamine equivalent daily
• The American Academy of Child and Adolescent Psychiatry establishes a maximum daily dose of 50mg for Adderall (mixed amphetamine salts), with some guidelines supporting up to 50-70mg total daily amphetamine dose for adults requiring extended coverage 1, 2
• Your proposed regimen falls comfortably within these limits 1, 2

Timing Considerations

• The 7:00am dosing of both medications together is appropriate, as Vyvanse reaches peak dextroamphetamine levels at approximately 3.5 hours post-dose, providing morning coverage 3
• The 2:00pm Dexedrine dose follows established guidelines that recommend giving the second stimulant dose preferably no later than 2:00pm to minimize insomnia risk 4, 2, 5
• The National Comprehensive Cancer Network specifically recommends that methylphenidate or dextroamphetamine's second dose should be given at lunch, preferably no later than 2:00pm 4, 5

Pharmacokinetic Rationale

• Vyvanse is a prodrug that requires enzymatic hydrolysis in red blood cells to release active dextroamphetamine, with a plasma elimination half-life of dextroamphetamine of approximately 10-11.3 hours in adults 3
• The immediate-release Dexedrine at 7:00am provides rapid symptom control while Vyvanse undergoes conversion 3
• The 2:00pm Dexedrine dose extends coverage into late afternoon/early evening without significantly interfering with sleep, given the timing cutoff 4, 2

Required Monitoring

• Check blood pressure and pulse quarterly, as small mean increases are expected with amphetamine therapy 2, 6
• Monitor weight at every visit to detect appetite suppression, which occurs in 25-39% of patients 2, 6
• Assess target ADHD symptoms using standardized rating scales at each visit 2
• Document side effects including insomnia, anorexia, headaches, irritability, anxiety, and tics 2, 6

Common Pitfalls to Avoid

• Do not administer the afternoon Dexedrine dose later than 2:00pm, as this increases insomnia risk 4, 2, 5
• Avoid escalating beyond maximum recommended total daily doses if tolerance develops; instead consider medication holidays or switching agents 2
• Do not crush or open Vyvanse capsules to attempt faster onset, as this destroys the prodrug mechanism and can cause dangerous immediate release 1

When This Regimen May Not Be Appropriate

• Active substance use disorder represents a relative contraindication to this combination 2
• Cardiovascular risk factors such as hypertension or structural cardiac abnormalities require careful evaluation before initiating 2
• Prohibitive side effects at lower doses should prompt consideration of alternative treatments rather than this combination 2

Documentation Best Practices

• Clearly state previous doses attempted and why they were insufficient 2
• Document current symptom severity using objective rating scales 2
• Note the absence of prohibitive side effects at the current dose 2
• Record blood pressure, pulse, and weight measurements at each visit 2