Is it recommended to take Vyvanse (lisdexamfetamine) 50mg and Dexedrine (dextroamphetamine) 5mg twice daily (bid)?

Combining Vyvanse 50mg and Dexedrine 5mg BID for ADHD

Yes, combining Vyvanse (lisdexamfetamine) 50mg with Dexedrine (dextroamphetamine) 5mg twice daily is a clinically acceptable strategy when a long-acting stimulant alone provides insufficient all-day symptom control, though the total daily amphetamine dose of approximately 60-65mg exceeds typical maximum recommendations and requires careful monitoring.

Understanding the Pharmacologic Rationale

• Vyvanse 50mg is a prodrug that converts to approximately 20mg of active dextroamphetamine over an extended period 1
• Adding Dexedrine 5mg BID provides an additional 10mg of immediate-release dextroamphetamine daily 2
• This combination yields a total daily amphetamine equivalent of approximately 60-65mg, which exceeds the FDA-recommended maximum of 70mg for lisdexamfetamine monotherapy but falls within a range sometimes used in clinical practice 1

Critical Dosing Considerations

The American Academy of Child and Adolescent Psychiatry recommends a maximum total daily amphetamine dose of 40mg, though clinical practice sometimes extends to 50mg 3, 4. Your proposed regimen exceeds this threshold, placing you in territory that requires heightened vigilance.

Timing Requirements

• Vyvanse 50mg must be taken immediately upon awakening to ensure morning coverage 1
• Both Dexedrine 5mg doses must be completed before 2:00-3:00 PM to prevent insomnia 2, 3
• The typical schedule would be: Vyvanse at 7 AM, Dexedrine at noon and 3 PM maximum 3

Mandatory Monitoring Parameters

When using this combination at higher total doses, you must monitor:

• Blood pressure and heart rate at every visit (quarterly minimum in adults) to detect hypertension or tachycardia 3, 4
• Weight at each visit to assess for appetite suppression and nutritional adequacy 3, 4
• Sleep quality and duration, as late-day dosing commonly causes insomnia 2
• Mood changes, irritability, and anxiety, which increase at higher amphetamine doses 3
• Signs of tolerance, dependence, or misuse, particularly at doses exceeding standard recommendations 1

Important Safety Caveats

Cardiovascular Risk

Higher amphetamine doses increase risk for:

• Hypertension and tachycardia 4
• Potential for sudden cardiac events in patients with underlying cardiac disease 1
• Perform baseline cardiac assessment including personal and family history of sudden death or arrhythmia before initiating this regimen 1

Dose-Response Ceiling

If maximum recommended doses fail to control symptoms adequately, increasing the dose further rarely provides additional benefit 4. Instead, consider:

• Switching to methylphenidate-based stimulants, as approximately 90% of patients respond when both amphetamine and methylphenidate classes are tried 5
• Adding non-stimulant medications (atomoxetine, guanfacine, clonidine) 3, 4
• Reassessing the diagnosis and evaluating for comorbid conditions affecting treatment response 3, 4

Alternative Approach to Consider

The American Academy of Child and Adolescent Psychiatry suggests that for patients on lisdexamfetamine 50mg requiring additional coverage, starting with dextroamphetamine 10-12.5mg total daily (split as 5mg BID or 5mg TID) represents a more conservative initial approach 5. Your proposed 10mg daily Dexedrine dose aligns with this guidance.

If This Combination Proves Insufficient

Rather than increasing doses further:

• Switch entirely to a different stimulant class (methylphenidate formulations) 5, 3
• Consider that inadequate response at maximum doses suggests the need for diagnostic reassessment rather than dose escalation 3, 4
• Evaluate medication adherence patterns, as twice-daily dosing shows higher rates of missed doses compared to once-daily regimens 6

Common Pitfalls to Avoid

• Do not give the afternoon Dexedrine dose after 2:00-3:00 PM, as this is the most common cause of treatment-related insomnia 2, 3
• Do not exceed 70mg total daily amphetamine equivalent without exceptional clinical justification and documentation 1
• Do not crush, chew, or divide Vyvanse capsules if attempting to adjust dosing, as this destroys the extended-release mechanism 1
• Do not continue escalating doses indefinitely if symptom control remains inadequate—this signals the need for a different therapeutic approach 3, 4