Converting Dexedrine To Other Stimulants

In our latest question and answer, our pharmacist discusses converting doses of Dexedrine (dextroamphetamine) to other stimulants.

Question

My pharmacy can no longer obtain the Dexedrine I have taken for many years. I will be prescribed a different medication, but my insurance coverage differs based on the dosage. Currently, I take 45 mg of Dexedrine (3 x 15 mg/day). Can you tell me what the equivalent dosage is for Zenzedi, Adderall, Ritalin, Vyvanse, and Concerta?

Asked by KiT On Feb 06, 2023

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Feb 06, 2023
Last updated Apr 20, 2024

Key points

  • Stimulant conversions are not exact and dosages need to be personalized for each patient.
  • Dexedrine and Zenzedi both contain only dextroamphetamine, so the conversion between them is 1:1.
  • Dexedrine is considered more potent than Adderall, Ritalin, Vyvanse, and Concerta on a per-milligram basis, but the exact conversion may vary for each individual.

Answer

Great question! I'm more than happy to provide some insight here but I want to preface my response by saying there is no direct, 1:1 conversion between Dexedrine (dextroamphetamine) and the other drugs you mentioned (with the exception of Zenzedi, since that also contains only dextroamphetamine).

Additionally, the dose of Dexedrine you are taking, 45mg, is on the high end (and is actually over the recommended dose of the drug, which is 40mg, if you are treating ADHD).

So, when I show approximate conversions, they are going to look high due to the fact you are already taking a high dose and the fact that dextroamphetamine is generally considered one of the more potent stimulants on a milligram-to-milligram basis.

I go over all the details in the next sections, but here is a quick rundown if you are running short of time to read through all this:

  • Stimulant conversions aren't an exact science and dosages need to be personalized on a per-patient basis
  • Dexedrine and Zenzedi both contain only dextroamphetamine, so the conversion between them is 1:1
  • Dexedrine is considered more potent than Adderall on a per-milligram basis. Some sources suggest that 1mg of Adderall is equivalent to around 0.83mg of Dexedrine
  • Dexedrine is considered more potent than Ritalin on a per-milligram basis. Some sources suggest that 1mg of Ritalin is equivalent to around 0.4mg of Dexedrine
  • Dexedrine is considered more potent than Vyvanse on a per-milligram basis. Some sources suggest that 1mg of Vyvanse is equivalent to around 0.32mg of Dexedrine
  • Dexedrine is considered more potent than Concerta on a per-milligram basis. Some sources suggest that 1mg of Concerta is equivalent to around 0.32mg of Dexedrine

What Is Dexedrine? 

First off, we have to understand what Dexedrine is and, it comes in two forms:

  • Dexedrine Spansules
  • Dexedrine tablets

Dexedrine Spansules contain dextroamphetamine and is considered an extended-release dosage form, even though it has a two-phased delivery. Per the prescribing information for the drug:

Each SPANSULE sustained-release capsule is so prepared that an initial dose is released promptly and the remaining medication is released gradually over a prolonged period.
Dexedrine Prescribing Information

Dexedrine tablets also contain only dextroamphetamine and are immediate-release.

You don't mention in your question if you are taking the extended-release or immediate-release Dexedrine, but based on how you worded your question, it seems as though you are taking the immediate-release tablets, 15mg, three times a day. Regardless, we have your total daily dose of Dexedrine, which is 45mg.

Dexedrine (Dextroamphetamine) To Zenzedi (Dextroamphetamine)

This is the easiest conversion since both Dexedrine and Zenzedi contain only dextroamphetamine. Therefore, it's a 1:1 conversion (i.e., 45mg Zenzedi is equal to 45mg Dexedrine).

Again, you didn't mention if you were taking an extended-release version of Dexedrine, so you would have to consider that if you are switching from one dosage form to another.

Dexedrine (Dextroamphetamine) To Adderall (Mixed Amphetamine Salts)

Adderall is a mixture of amphetamine salts and dextroamphetamine salts, which produces a 3:1 ratio of two different enantiomers of amphetamine, dextroamphetamine (also referred to as d-amphetamine), and levoamphetamine (also referred to as l-amphetamine). This is described in the prescribing information for the drug:

ADDERALL® tablets contain d-amphetamine and l-amphetamine salts in the ratio of 3:1.
Adderall Prescribing Information

Adderall, being a 3:1 ratio, is sometimes referred to as being 75% dextroamphetamine (d-amphetamine) and 25% levoamphetamine (l-amphetamine).

When it comes to amphetamines, the dextro-isomer is considered to be the stronger one, but the levo-isomer also plays a role in its therapeutic effects. Thus, converting between something like Dexedrine (which only contains dextroamphetamine) and Adderall (which contains dextroamphetamine and levoamphetamine) can not be done with precision and needs to be customized for each individual patient.

Nevertheless, one source recommends a dose conversion by a factor of 0.83 (i.e., 1mg of Adderall is equivalent to 0.83mg of Dexedrine). This is essentially an assumption that Adderall is 83% as potent as dextroamphetamine on a per-milligram basis. Again, this isn't an exact figure and will vary by individual, but it can represent a good starting point.

So, in your case, if you take 45mg of Zenzedi, that would equal around 54 mg of Adderall (i.e., 83% of 54 mg of Adderall is approximately 45mg of Dexedrine).

Dexedrine (Dextroamphetamine) To Ritalin (Methylphenidate)

Ritalin contains methylphenidate. Methylphenidate is not an amphetamine but is nonetheless a similar type of stimulant.

Since methylphenidate is a different type of stimulant than amphetamine, this conversation is more difficult than converting between amphetamines, and again, not an exact science.

A general rule of thumb though is that Adderall is twice as potent as Ritalin. Since Dexedrine, as talked about in the section above, is considered more potent than Adderall, Dexedrine would be slightly more than twice as potent as Ritalin (i.e., you need more than double the dose of Ritalin to be equivalent to Dexedrine).

Based on this, a commonly used conversion factor here is 0.4 (i.e., 1mg of Ritalin is equivalent to 0.4mg of Dexedrine)

Going back to your case, taking 45mg of Dexedrine would equal around 112.5mg of Ritalin (i.e., 40% of 112.5mg of Ritalin is 45mg of Dexedrine).

It is important to note in this conversion, 112.5mg of Ritalin would be over the maximum daily dose of the drug set by the FDA. This is where we get into the fact this isn't an exact science, and dosages need to be adjusted on a per-patient basis. It's also why some sources recommend a more conservative straight 0.5 conversation factor here (i.e., Ritalin 1 mg is equivalent to 0.5 mg of any form of amphetamine). This would bring your conversion of Dexedrine 45mg down to 90mg of Ritalin.

Dexedrine (Dextroamphetamine) To Vyvanse (Lisdexamfetamine)

This is also a challenging conversion because Vyvanse has an interesting pharmacokinetic profile.

Vyvanse contains lisdexamfetamine. Lisdexamfetamine is a prodrug that is converted to dextroamphetamine by the red blood cells.

Even though Vyvanse is converted to dextroamphetamine (the active ingredient in Dexedrine) in your body, this is not a 1:1 conversion.

The dose of Vyvanse is generally higher than if you were using 'plain' dextroamphetamine since the lisdexamfetamine drug molecule contains the amino acid lysine. This amino acid adds to the molecular weight of the drug (and the milligram dose) but not to the overall therapeutic activity.

Sources vary slightly on the conversion factor here, but most are around 0.29-0.32 (i.e., 1mg of Vyvanse is equivalent to 0.32mg of Dexedrine)

If you are taking 45mg of Dexedrine, that would equal 140mg of Vyvanse (i.e., 0.32% of 140mg of Vyvanse is around 45mg of Dexedrine). Now, this is well above the maximum daily dose of Vyvanse, which is 70mg, so it's unlikely you'll get the desired clinical response if you took Vyvanse at the recommended dosages.

Dexedrine (Dextroamphetamine) To Concerta (Methylphenidate)

Concerta is an extended-release version of methylphenidate.

This is likely the most difficult conversation to get exactly right due to two reasons:

  • We are going from amphetamine to methylphenidate (two different types of stimulants).
  • Concerta tends to need to be dosed a little higher than a total equivalent daily dose of immediate-release methylphenidate to have the same clinical effect.

Several sources suggest that 1mg of Concerta is equivalent to around 0.83mg of immediate-release methylphenidate. This is essentially what the prescribing information for Concerta states, as seen in the conversion chart below:

Methylphenidate to Conerta

So, if we took what we converted above, Dexedrine to Ritalin, which was 112.5mg, and use our conversion factor of 0.83mg of immediate-release methylphenidate to 1mg Concerta, that equals around 135mg of Concerta. This, like with Vyvanse, is above the maximum daily dose of the drug.

Final Words

I hope you found this answer helpful. Please be sure to speak with your doctor regarding your options.

Since you are on quite a high dose of dextroamphetamine, I would imagine switching to another form of dextroamphetamine may be sure best bet. Additionally, you mentioned you were having insurance issues and a lot of the conversions I wrote about above are on the high end, and sometimes, over the maximum dosage set by the FDA. You'll almost certainly have issues having your insurance cover a dosage that is not FDA-approved.

Again, speak with your doctor to find the treatment that works best for you and your medical situation.

Thanks for reaching out!

References

  • Dexedrine Prescribing Information, AccessFDA
  • Stimulant Equivalency Table, Matt Swenson, MD, StudyLib
  • How to Switch Stimulants: A Dosing Guide for ADHD, Psychiatric Times
  • Concerta Prescribing Information, AccessFDA
  • Adderall Prescribing Information, AccessFDA
  • Vyvanse Prescribing Information, Shire

About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 13 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical, program development, and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Dr. Brian Staiger also has herbalist training and educational certificates in the field of medical ethnobotany. Feel free to send him an email at [email protected]! You can also connect with Dr. Brian Staiger on LinkedIn.

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