What is 40 mg of Vyvanse Equal to in Adderall?

Vyvanse and Adderall are two of the most commonly prescribed medications for ADHD (Attention-Deficit/Hyperactivity Disorder). Both are stimulant medications, but they differ in how they are formulated, how they are metabolized, and how long they last in the body. One question patients often ask is: “If I take 40 mg of Vyvanse, what does that equal in Adderall?” Let’s break this down step by step.

Understanding Vyvanse

Vyvanse (lisdexamfetamine) is a prodrug of dextroamphetamine. This means it is inactive until it is metabolized by the body. Once processed, it converts into dextroamphetamine, which provides its therapeutic effects. Vyvanse is designed for long-lasting, steady symptom control, often lasting up to 12–14 hours.

Understanding Adderall

Adderall is a combination of amphetamine salts—specifically dextroamphetamine and levoamphetamine. It is available in both immediate-release (IR) and extended-release (XR) forms. The effects of Adderall generally last between 4–6 hours for IR and 10–12 hours for XR.

Conversion Between Vyvanse and Adderall

Because Vyvanse is a prodrug, the milligram-to-milligram comparison is not direct. In general, the accepted clinical conversion is:

• 30 mg of Vyvanse ≈ 10 mg of Adderall IR (dextroamphetamine base equivalent).

Using this guideline:

• 40 mg of Vyvanse ≈ about 13–15 mg of Adderall IR.

This means if you are prescribed 40 mg of Vyvanse, it would roughly correspond to the effects of around 15 mg of Adderall immediate-release.

Important Considerations

1. Individual Response Varies: Not everyone responds to stimulant medications the same way. Some people may feel that 40 mg of Vyvanse feels stronger or weaker compared to 15 mg of Adderall.
2. Duration of Action: Vyvanse usually lasts longer in the body, providing a smoother effect throughout the day, while Adderall IR may wear off sooner.
3. Formulation Differences: Adderall XR is designed to last longer than Adderall IR, so the comparison may differ depending on which version you are prescribed.
4. Doctor Supervision: Only a qualified healthcare provider should adjust your dosage. Switching between Vyvanse and Adderall requires medical supervision to ensure safety and effectiveness.

Final Thoughts

So, what is 40 mg of Vyvanse equal to in Adderall? Roughly 13–15 mg of Adderall IR. However, the comparison isn’t exact because the two drugs differ in how they’re metabolized and how long they last. Always follow your doctor’s instructions when switching between ADHD medications, and never adjust your dosage without medical guidance.