View Full Version : No motivation to do homework... are the meds becoming less effective?

10-07-12, 12:37 PM
Hey guys Im prescribed 40 mgs of Vyvanse and at first it worked out perfect but Im having a serious lack of motivation to do homework, something I haven't had a problem with since pre-diagnosis. I've been on this dosage for 3 months or so and Im noticing that while the potency hasn't decreased, the duration has. I find this strange. Vyvanse is supposed to last 14 hours yet its done by 8th period. I have no idea what the cause is. Is it in my head? Is it lack of motivation? Or is it something I should look into with my GP?

10-07-12, 01:15 PM
My doctor once told me , that the duration since it's a prodrug may vary from your case to clinical studies also taking it with any fat food may extend the on-set time in one hour , making you have a longer duration of the med and a slower onset, there are some other possibilities too like hormonal changes and your body building resistance to the drug.

Try to eat more and better before taking the med , and during the effect of the med. if it do not solve the problem talk with your doctor.

10-07-12, 02:04 PM
After some quick research I've found that vyvanse half-life may vary from 13,8h to 16,7h depending on how your body is eliminating the med and how much fat was in what you ate with the med, but this calculation is for the half-life of the med , depending on how much you need in your blood to feel the effects you may fell it lasting longer or shorter.

Here's a nice graphic representation of how much med is in your blood after taking the med (70mg pill in the graph). extracted from this study

10-09-12, 05:11 PM
thanks for the link