What is the recommended dose of methylphenidate (Extended Release) when switching from Adzenys XR (Amphetamine Extended Release) 12.5mg in a patient with Attention Deficit Hyperactivity Disorder (ADHD)?

Methylphenidate ER Dosing When Switching from Adzenys XR 12.5mg

There is no established direct conversion ratio between amphetamine-based medications (Adzenys XR) and methylphenidate formulations, so you should start methylphenidate ER at a low initial dose (typically 18-20mg for long-acting formulations) and titrate based on clinical response rather than attempting mathematical dose equivalence. 1

Rationale for Starting Approach

• Amphetamine and methylphenidate have different mechanisms of action: Amphetamines both inhibit dopamine reuptake AND cause direct release of monoamines, while methylphenidate primarily blocks reuptake without causing release 2
• Different potency profiles: Amphetamines generally have longer plasma half-lives and different pharmacokinetic properties compared to methylphenidate, making direct dose conversion unreliable 3, 2
• Individual variability is substantial: Response to one stimulant class does not predict equivalent dosing needs for another stimulant class 1

Recommended Switching Protocol

Initial Dosing Strategy

• Start with methylphenidate ER 18-20mg once daily (for formulations like Concerta) or equivalent dosing for other ER preparations 1
• For immediate-release methylphenidate, consider starting at 5-10mg twice daily if using IR formulations 1
• Administer in the morning to minimize sleep disturbances 4

Titration Schedule

• Increase by 5-10mg increments weekly based on symptom control and tolerability 5
• Allow at least one week between dose adjustments to properly evaluate response 4
• Maximum doses typically range up to 54-72mg daily for long-acting methylphenidate formulations, though some patients may require higher doses 1

Monitoring Parameters During Switch

Efficacy Assessment

• Use standardized ADHD rating scales at each dose adjustment to objectively measure symptom control 1, 5
• Evaluate both core ADHD symptoms (inattention, hyperactivity, impulsivity) and functional outcomes 1
• Assess duration of symptom coverage throughout the day, as different ER formulations have varying pharmacokinetic profiles 3

Safety Monitoring

• Cardiovascular parameters: Monitor blood pressure and heart rate at each visit, as both stimulant classes can cause cardiovascular effects 4, 5
• Growth parameters: Track weight and height in children/adolescents, as stimulants can affect growth rates 1
• Common adverse effects: Assess for decreased appetite, insomnia, irritability, and mood changes 1, 4
• Behavioral changes: Watch for emotional reactivity or rebound symptoms as medication wears off 1, 4

Important Clinical Pitfalls to Avoid

• Do not assume dose equivalence: The 12.5mg of Adzenys XR does not translate to a specific methylphenidate dose through simple calculation 1, 3
• Avoid starting at too high a dose: This is a common error that increases side effect burden and may lead to premature discontinuation 4
• Do not rush titration: Insufficient time between dose changes prevents accurate assessment of therapeutic response 4
• Consider formulation differences: Various methylphenidate ER products have different release profiles (biphasic, ascending, etc.) that affect symptom coverage patterns throughout the day 1, 3

Alternative Considerations

• If the patient had inadequate response to Adzenys XR at 12.5mg, this may inform your methylphenidate titration target, potentially requiring higher doses 1
• If switching due to tolerability issues with amphetamines, methylphenidate may offer a better side effect profile for some patients 2
• Consider non-stimulant options (atomoxetine, viloxazine, guanfacine, clonidine) if both stimulant classes prove problematic 1