Can I switch a patient from Adderall (amphetamine and dextroamphetamine) 60mg Immediate Release (IR) a day to methylphenidate 60mg IR a day?

Direct 1:1 Dose Conversion is Not Appropriate

You cannot simply switch a patient from Adderall 60mg IR daily to methylphenidate 60mg IR daily using a 1:1 dose conversion, as these medications have different potency ratios and this approach would likely result in inadequate symptom control.

Understanding the Dose Equivalence

The evidence indicates that amphetamine-based stimulants (like Adderall) and methylphenidate are not equipotent on a milligram-per-milligram basis:

• Adderall contains mixed amphetamine salts that are approximately twice as potent as methylphenidate 1
• A retrospective comparison found that Adderall and methylphenidate provided comparable efficacy at different dose ranges, with Adderall typically requiring lower total daily doses 1
• The typical dose range for methylphenidate IR is 5-60 mg/day, while for dextroamphetamine (a component of Adderall) it is 5-30 mg/day 2

Recommended Conversion Strategy

The appropriate conversion ratio is approximately 2:1 (methylphenidate:amphetamine). For a patient on Adderall 60mg daily, you should consider starting methylphenidate at approximately 120mg daily, though this exceeds standard maximum recommendations and requires careful consideration.

Critical Dosing Considerations

• The PDR maximum for methylphenidate IR is 60mg total daily dose 2
• Your patient's current Adderall dose of 60mg daily is already at the upper limit for amphetamines (PDR maximum 40mg) 2
• Consensus expert opinion suggests that doses may occasionally go higher than PDR limits, with some experts limiting methylphenidate to 40mg total daily when given in multiple doses, or up to 25mg for a single dose 2

Practical Switching Algorithm

Given the high dose involved, consider this approach:

1. Start methylphenidate at 60mg total daily (the PDR maximum), divided into 2-3 doses 2
2. Use a gradual cross-titration rather than abrupt switching to minimize risk of symptom exacerbation 3
3. Titrate upward in weekly increments of 5-10mg per dose if symptom control is inadequate 2
4. Monitor closely for efficacy and adverse effects during the first 2-4 weeks of titration 2

Important Caveats

• This patient may require methylphenidate doses above standard recommendations to achieve equivalent symptom control, given their high Adderall dose 2
• Methylphenidate has a shorter duration of action (2-4 hours) compared to Adderall, requiring more frequent dosing 4, 1
• Consider extended-release formulations to reduce dosing frequency and improve compliance, though this changes the conversion strategy 2
• Sleep problems and decreased appetite are common adverse effects that may worsen with higher methylphenidate doses 2, 5

Monitoring During Transition

• Assess ADHD symptoms weekly using standardized rating scales from both patient and collateral sources 2
• Check vital signs regularly, as both medications can cause hypertension and tachycardia 2
• Evaluate for common adverse effects including insomnia, agitation, and appetite suppression 2, 5

The key point: A 60mg Adderall dose likely requires 100-120mg methylphenidate for equivalent effect, but this exceeds standard maximums and necessitates careful clinical judgment, close monitoring, and potentially consideration of alternative ADHD medications or extended-release formulations.