Is Adderall XR (mixed amphetamine‑dextroamphetamine) half as potent as Focalin XR (dexmethylphenidate) on a milligram‑for‑milligram basis?

Adderall XR vs Focalin XR: Relative Potency

No, Adderall XR is not half as potent as Focalin XR on a milligram-for-milligram basis—the two medications have roughly equivalent efficacy at comparable doses, though individual response varies significantly. 1

Direct Comparative Evidence

A head-to-head double-blind crossover study directly compared extended-release dexmethylphenidate (Focalin XR) and extended-release mixed amphetamine salts (Adderall XR) at identical doses (10,20, and 25-30 mg) in 56 children and adolescents with ADHD 1:

• Both medications showed equivalent efficacy at the same dose levels, with approximately 79-80% of patients demonstrating reliable improvement on the ADHD Rating Scale-IV at the highest doses 1
• Dose level, rather than stimulant class, was the primary determinant of response, meaning higher doses of either medication produced better outcomes regardless of which specific stimulant was used 1
• Individual response patterns varied substantially: approximately 43% of responders showed preferential response to only one of the two stimulant formulations, despite equivalent group-level efficacy 1

Clinical Implications for Dosing

The American Academy of Pediatrics emphasizes that individual response to methylphenidate versus amphetamine is idiosyncratic, with approximately 40% responding to both medications and 40% responding to only one 2. This means:

• You cannot predict which medication will work better for a specific patient based on ADHD subtype or other clinical characteristics 2
• Systematic trials of both medication classes are often necessary to identify the optimal agent for each individual 3
• True nonresponse to stimulants is extremely rare (approximately 2%) when both methylphenidate and amphetamine preparations are tried across an adequate dose range 3

Dosing Strategy

Titrate both medications to maximum benefit with minimum adverse effects rather than using fixed milligram-per-kilogram ratios 2:

• Start at lower doses (10-20 mg for either medication) and increase systematically every 3-7 days based on response 2, 1
• Both medications show dose-dependent improvements, particularly for hyperactivity/impulsivity symptoms 1
• Monitor for common adverse effects including decreased appetite and insomnia, which increase at higher doses for both medications 1
• Maximum FDA-approved dose for Adderall XR is typically 30 mg daily for children and up to 70 mg for lisdexamfetamine (Vyvanse, a related amphetamine prodrug) 4

Pharmacological Differences

While clinical efficacy is comparable, the medications have distinct pharmacological profiles 5:

• Adderall contains approximately 75% dextroamphetamine and 25% levoamphetamine, whereas Focalin contains only dexmethylphenidate (the active isomer of methylphenidate) 5
• The levoamphetamine component in Adderall may alter dopamine release kinetics, producing faster rise times and shorter signal decay times compared to pure dextroamphetamine 5
• These pharmacokinetic differences may explain why some patients respond preferentially to one medication over the other despite equivalent group-level efficacy 1, 5

Common Pitfalls to Avoid

• Do not assume equivalent milligram-for-milligram conversion ratios between these medications—they are not interchangeable at a 2:1 or any other fixed ratio 1
• Do not abandon stimulant treatment after failure of one agent—try the alternative stimulant class before concluding the patient is a nonresponder 3
• Do not exceed FDA-approved maximum doses (70 mg for amphetamine-based medications) without compelling justification, as cardiovascular and psychiatric risks increase substantially 4
• Monitor cardiovascular parameters regularly, as both medications increase heart rate by 1-2 beats per minute and blood pressure by 1-4 mm Hg on average, with 5-15% of patients experiencing more substantial increases 6