Understanding Vyvanse

[scriptx]

Disclaimer: I'm only self-taught, to a meager extent, in the area of pharmaceuticals like pharmacokinetics, pharmacodynamics, or any other pharmaco-. Please feel free to poke holes in any theories, assumptions, or "proofs" that I may provide, take for granted, or posit. Please help me to understand how these all tie in in regards to the workings of Vyvanse.

According to Wikipedia (Lisdexamfetamine), only 28% of a Vyvanse dose is bioavailable via an oral route. Defining further, bioavailability is the amount of administered drug that reaches the circulatory system. Now because Vyvanse is a prodrug it "[has to be converted] into dextroamphetamine via enzymes in the red blood cells...."

Pulling again from the Vyvanse Wikipedia page, "...each milligram of lisdexamphetamine is equivalent to 0.2948 mg of dextroamphetamine base." So, if only 28% of a 40mg Vyvanse dose gets into my bloodstream (and requires conversion by RBC enzymes) then:

• 28% of 40mg is 11.20mg dextroamphetamine base* that makes it into my bloodstream
• And 11.20mg multiplied by the 0.2948mg ratio is 3.3017mg
• Does this mean that only 3.30mg of active dextroamphetamine base is being converted and used in my blood stream?

* I'm operating under the assumption that dextroamphetamine base is what is useable by my body; if we were talking about dextroamphetamine HCl I understand that the HCl is what keeps the molecule from breaking down prematurely.

• What happens to the other 72% of my Vyvanse dose?
• What happens to the other 28.8mg would-be dextroamphetamine base?

 

[Dexed]

The math was done wrong.

40mg Vyvanse (your dose) is multiplied by .2948 to give 11mg d-amp (remember your sig figs) in order to know how much is actually d-amphetamine base. Abosorbtion (orally) of Vyvanse is near 100%. Don't fret.

 

[NeighborhoodThreat]

^Well said.

Don't worry about it.

Your Vyvanse is working just fine.

 

[weekend addiction]

Hahaha I still don't understand that goddamn drug. Sometimes I get anxious on it other times it relaxes me. Sometimes it seems to do both at the same time. A weird ass chemical...