What is the equivalent dose of Adderall (amphetamine and dextroamphetamine) ER when converting from methylphenidate (Ritalin) ER 45 mg?

Methylphenidate ER 45 mg to Adderall ER Conversion

When converting from methylphenidate ER 45 mg to Adderall ER, start with Adderall ER 20-25 mg once daily using the established 2:1 conversion ratio (methylphenidate:amphetamine), then titrate based on clinical response. 1

Conversion Ratio and Starting Dose

• The American Academy of Child and Adolescent Psychiatry establishes a 2:1 conversion ratio (methylphenidate:amphetamine), meaning 45 mg of methylphenidate ER converts to approximately 22.5 mg of Adderall ER 1
• Round to practical dosing: start with Adderall ER 20 mg once daily, as this represents the closest available dose strength and accounts for individual variability in response 2, 1
• The typical dose range for methylphenidate is 5-60 mg/day, while for amphetamines (Adderall) it is 5-40 mg/day, confirming the approximate 2:1 ratio 1

Titration Algorithm After Initial Conversion

• Week 1: Start Adderall ER 20 mg once daily in the morning, discontinue methylphenidate ER immediately (no cross-taper needed) 2, 1
• Week 2: If symptom control is inadequate, increase to Adderall ER 25 mg once daily 2, 1
• Week 3-4: If further improvement needed, increase by 5 mg weekly increments up to maximum of 40 mg daily (standard maximum for amphetamines) 2, 3
• Obtain ADHD rating scales from teachers/parents weekly during titration to objectively assess response 2

Critical Monitoring Parameters

• Assess at each visit: Blood pressure, pulse, weight, appetite, sleep quality, and behavioral symptoms using standardized ADHD rating scales 2, 3
• Common adverse effects to monitor: Decreased appetite, insomnia, headache, and irritability—these may worsen with higher doses 1, 3
• Most patients (approximately 70-90%) respond to either methylphenidate or amphetamine class, but about 43% show preferential response to one class over the other 2, 4

Important Caveats and Pitfalls

• Do not assume 1:1 equivalence—methylphenidate requires roughly double the dose of amphetamine for equivalent effect 1
• The 2:1 ratio is a starting point; individual patients may require doses above or below this conversion due to pharmacokinetic differences and individual response variability 1, 4
• Maximum recommended daily dose for Adderall is 40 mg per FDA guidelines and expert consensus, though some patients may require up to 50 mg in adults 3
• Extended-release amphetamine formulations (Adderall XR) provide approximately 8-9 hours of coverage, which may be shorter than some methylphenidate ER formulations that provide up to 12 hours 5
• If the patient was stable on methylphenidate ER 45 mg, starting at the lower end (20 mg Adderall ER) allows for upward titration while minimizing risk of excessive dosing and adverse effects 2, 1

Duration of Action Considerations

• Adderall ER provides 8-9 hours of symptom control compared to some methylphenidate ER formulations (like Concerta) that provide 10-12 hours 5
• If afternoon symptom breakthrough occurs, consider adding a small immediate-release booster dose (5 mg) in early afternoon rather than increasing the morning ER dose 2
• Schedule the morning dose early enough to allow for adequate coverage throughout the school/work day 2