What is the equivalent dose of Focalin (dexmethylphenidate) for a patient taking Ritalin (methylphenidate) 15mg twice daily (bid) for Attention Deficit Hyperactivity Disorder (ADHD)?

Converting Ritalin 15mg BID to Focalin

The equivalent dose of Focalin (dexmethylphenidate) for a patient taking Ritalin (methylphenidate) 15mg twice daily is 7.5mg twice daily, using a 2:1 conversion ratio. 1, 2

Conversion Rationale

• Dexmethylphenidate contains only the d-threo-enantiomer (the active isomer) of methylphenidate, while Ritalin contains both d- and l-enantiomers in equal amounts 1
• The standard conversion is 2:1 (methylphenidate:dexmethylphenidate), meaning dexmethylphenidate provides equivalent efficacy at half the dose of racemic methylphenidate 1, 2
• Clinical trials demonstrated that an average dose of 18.25 mg/day of dexmethylphenidate provided equivalent efficacy to 32.14 mg/day of racemic methylphenidate, confirming the approximately 2:1 ratio 2

Specific Dosing Recommendation

• Convert the patient's current total daily dose of 30mg Ritalin (15mg BID) to 15mg total daily dose of Focalin (7.5mg BID) 1, 2
• Focalin is available in 2.5mg, 5mg, and 10mg tablets, so prescribe 5mg + 2.5mg tablets for each dose, or use two 5mg tablets if 7.5mg is unavailable and round to 5mg BID initially 1
• No cross-taper is necessary when switching between methylphenidate formulations—start Focalin the day after stopping Ritalin 3

Duration of Action Consideration

• Immediate-release dexmethylphenidate may have a longer duration of action than immediate-release racemic methylphenidate after twice-daily dosing, with efficacy extending into late afternoon (6:00 PM assessments showed superiority over placebo) 2
• If the patient requires full-day coverage, consider Focalin XR (extended-release dexmethylphenidate) instead, which provides 8-12 hours of symptom control with once-daily dosing 4, 5
• Focalin XR uses a bimodal release profile that mimics two doses of immediate-release dexmethylphenidate given 4 hours apart 4, 5

Monitoring After Conversion

• Assess ADHD symptom control within the first week, particularly monitoring coverage throughout the day including late afternoon/evening 2
• Monitor for typical methylphenidate adverse effects including appetite suppression, insomnia, irritability, and cardiovascular effects (blood pressure and heart rate) 5
• If symptom control is inadequate at 7.5mg BID, titrate upward in 2.5-5mg increments per dose 5

Common Pitfalls to Avoid

• Do not use a 1:1 conversion ratio—this would result in underdosing and treatment failure 1, 2
• Do not assume identical duration of action between formulations without monitoring—individual response varies 2
• Avoid administering the second daily dose too late in the day (after 2:00 PM) to minimize insomnia risk 3