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The Adderall Shortage: what to prescribe and how to convert doses


Adderall is in short supply at the moment, which has led to shortage of substitution amphetamines.

What to do?

For a patient taking Adderall, I feel the best approach is, prior to issuing the prescription, asking the patient (or staff) to call their pharmacy to confirm that their dose is available in the quantity needed. Calling around to other pharmacies is not ideal, and some pharmacies are declining to fill Adderall scripts for nonregular customers.

If Adderall is unavailable, they should inquire about availability of possible alternatives:

  1. Generic Adderall in other mg strengths (5, 7.5, 10, 12.5, 15, 20, 30 mg) to combine or split

  2. Generic Adderall XR

  3. Generic Dexedrine immediate release

  4. Generic Dexedrine Spansule (extended release capsules) if Dexedrine IR is unavailable

  5. Vyvanse, which may be available generically within a year. Savings card available for individuals with private insurance

  6. Generic Ritalin (methylphenidate), although for adults it is generally less effective than Adderall

How to convert doses:



Conversion from Adderall 20 mg

​Duration of action

​Appetite suppression

​Adderall (mixed amphetamine salts)


5, 7.5, 10, 12.5, 15, 20, 30 mg

​Usually BID

5 hr


Adderall XR


5, 10, 15, 20, 25, 30 mg

​Same Adderall dose combined to QD

10 hr




​5, 10 mg

​20 mg Adderall = 15 mg Dexedrine (may need to divide TID)

4 hr

More than Adderall

Dexedrine Spansule (ER)


5, 10, 15 mg

​As above, combined to QD

​8 hr

More than Adderall

Vyvanse (lisdexamfetamine)


10, 20, 30, 40, 50, 60, 70 mg

20 mg Adderall = 50* mg Vyvanse, combined to QD

​10-14 hr

More than Adderall

Ritalin (methylphenidate)


​5, 10, 20 mg

​20 mg Adderall = 40 mg Ritalin (often divided TID)

4 hr

​Less than Adderall

*If converting to Vyvanse, advise taking it as early as possible in the morning to avoid insomnia, and also because onset of benefit is delayed up to 90 minutes as the prodrug (lisdexamfetamine) is cleaved to dextroamphetamine in red blood cells. Although 20 mg of Adderall is equivalent to 50 mg of Vyvanse, some individuals respond differently so round down on the conversion. Consider only doubling the Adderall mg dose to arrive at the starting Vyvanse dose.

The Shortage



  • More people taking Adderall due to relaxed online prescribing laws during the pandemic, when stimulant prescriptions increased by 16%.


  • Teva pharmaceuticals, the main manufacturer of generic Adderall, is having difficulty keeping up.

How long?

The shortage is expected to continue at least until March 2023.

What should you tell patients looking to buy Adderall on the street?

Many street versions of Adderall are laced with fentanyl.

Comparing dextroamphetamine to levoamphetamine

Dextroamphetamine (D-amp) and levoamphetamine (L-amp) are similar drugs but not exactly the same. One may be better for hyperactivity, the other better for inattention although it is unclear which is which (Sagvolden and Xu, 2008; Arnold et al, 1972).

Amphetamine preparations contain either

  1. Only D-amp (Dexedrine, Vyvanse as a prodrug)

  2. More D- than L-amp (Adderall)

  3. Racemic: 50% D- and 50% L-amp (Evekeo, formerly Benzedrine)

No formulation has more levoamphetamine than dextroamphetamine.

Table comparing dextroamphetamine to levoamphetamine adderall dexedrine vyvanse

Why is pure L-amphetamine not produced?

Peripheral effects (elevated blood pressure and heart rate) would be excessive at the dose of pure levoamphetamine necessary to treat ADHD.

Comparing Adderall to Dexedrine

How is Adderall (75% D-amphetamine) different from Dexedrine (100% D-amphetamine)?

The main advantage of generic Adderall ($10+) over Dexedrine ($20+) is cost. Adderall is better if less appetite suppression is desired.

Advantages of Adderall (75% D-amp) over Dexedrine (100% D-amp)

  • Price ($10+ vs $20+)

  • Slightly longer duration of action (5 hours vs 4 hours)

  • More available mg strength tablets

  • Less appetite suppression

Advantages of 100% D-amp over Adderall

  • More appetite suppression

  • Potentially less elevation of heart rate and blood pressure

  • Best abuse-deterrent option (Vyvanse, which is 100% prodrug of D-amp)

  • Transdermal option (Xelstrym)

Visual Mnemonics

There are over 20 preparations of stimulant medication for ADHD. If a patient inquires about "Mydayis", prescribers may struggle to recall anything about it-- maybe that it is a long-acting ADHD med--but is it an amphetamine or a methylphenidate?

Cafer's Psychopharmacology: Visualize to Memorize 270 Medication Mascots PDF download has visual mnemonics for all of the variations. The main feature of stimulant mascots is that amphetamine pictures include an amplifier, while methylphenidates include a Scantron sheet--"Write a line" (for Ritalin) on "math final date" for methylphenidate.

methylphenidate ritalin compared to adderall amphetamine mixed amphetamine salts

Comparison tables

comparison table for formulations of amphetamine adderall etc

table comparing formulations of methylphenidate ritalin etc

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