Why do I get sleepy after taking Vyvanse or Adderall?

It's most likely what's called an IDR or idiosyncratic drug reaction. These reactions are adverse drug reactions that do not occur in most patients at any dose and do not involve the known properties of the drug.
There really isn't a good explanation for what causes them or why they occur so rarely.
Wildcat

It's a sign of overdose

I just wanted to thank everyone who commented

I have ADHD! Im on vyvanse and basically my specialtist told me the meds increases your normally depleted levels of serotonin, norepinephrine, and dopamine and these help your brain calm down and relax you so you can focus better. I could fall asleep after taking my meds! Also, the stimulant effects wear off once your body can tolerate it and you don't get so sleepy

I have started on stimulants with adderall XR 20 mg once per day recently as I went undiagnosed for 28 years. I have had a similar effect to yours where it gives me the effect of something in the middle of being relaxed and sleepy but I actually never end up sleeping. As someone has mentioned in this thread that it could be the dosage you take and since our brains are not that used to dopamine releases the stimulants end up being consumed to make us extremely relaxed to a point where I struggle with focusing on my day to day stuff. I personally think I need to be on a higher dose that would be enough to calm my brain but also start stimulating it. I have my psych appointment coming up soon so I will report back with an update.
This thread is extremely helpful and please consult with your provider before making a change because stimulants are no joke!

My doctor warned me about this potential side effect and explained it's usually a dosing issue. I'll explain it the way I had to think about it to understand it: The part of your brain that the drug speeds up to combat ADD is slowed down by a natural reaction from your brain to the medication trying to "speed it up." If this happens it can mean a dosage increase may be necessary to force your brain beyond the ability to slow itself down in reaction to the medicine. Speak with your doctor about the symptom(s) you are experiencing. While I couldn't say if this explaination applies to you, I can say that it would be a mistake to assume that all feelings you experience on a drug or medication are the same as what everyone else experiences. So make your doctor earn their paycheck! Good luck!

One of the things I’ve noticed about this happening is when I don’t get enough sleep the night before. I was taking two Teva Brand immediate release of Adderall 30mg twice daily and I would just start to crash around 6:00pm. I told my Psychiatrist and he put me one one Adderall 30mg in the morning and I take a 70mg Vyvanse at noon and I don’t have the crash now. I stay up a little later than I use to, but I have not crashed as often in the afternoon. My body doesn’t seem to react the same to extended release medications and sometimes the Vyvanse will start working much later and I don’t get as much sleep. The equivalent of the Vyvanse is something like 33.7mg of Adderall.

I read some of these post where people are taking like 120 mgs of Adderall and higher daily. 60 mgs is the limit in Texas. If I take more than 60mgs , I will get a UTI! The state logs every controlled substance that is prescribed and no pharmacy will fill anything higher than 60mg a day.

I get sleepy too. I don't get it

Hey there! The answer to your question is very simple. The fluoxetine you’re taking is the problem. I was on fluoxetine for the longest time before I start taking Vyvanse again. So I know how fluoxetine blocked the the full effect of Vyvanse on me. At some point my psychiatrist discontinued the fluoxetine, thank God. Best decision ever. SSRI aren’t for everyone.

I have the same issue with Adderall but not ritalin. I decided to take a break from ritalin and try Adderall. Which I have done before to help my ritalin tolerance. I use Adderall for a week or 2 and go back and I see to feel the ritalin more. It’s so strange to me that ritalin doesn’t make me sleepy but Adderall is making me feel like I took a sedative. But when I tried Adderall a couple years ago it didn’t make me sleepy but did zone me out too much. In fact it gave me insomnia before but I was able to wake up on time. I wonder if anyone has used a ritalin booster while on Adderall. I know some who use long lasting adhd meds use an immediate release stimulate as a booster. I know ritalin and Adderall work differently. I will add now I’m on viibryd which is an SNRI Anti depressant and before when I tried Adderall I was on Zoloft it no SSRI. So maybe the combo is making me so sleepy. I hate it. Defeats the purpose of me taking a stimulant.

Whats the difference between Adderall and Vyvanse? i know if i take Ritalin it helps with my energy and feeling of wanting to do things . I have 20 years of chronic fatigue. Adderall helped in the beginning the 10mg XR but it doesnt seem to do anything any more. I am wondering if I might need to go up on dose or switch?

Working in the health care industry, and having 2 children on stimulants, I've been told that your mind is "racing" and when given a stimulant such as coffee or medication it settles your mind to a sense of calm. People who do not have ADHD/ADD would become wired off a stimulant. I actually give the boys their last dose of the day at bedtime to settle their minds so they actually sleep. My one child is on Vyvanse, and hes super sleepy, we may lower the dose if it doesnt adjust in his system soon.

Fluoxetine could be the culprit. I take Adderall (20 mg in the morning and 20 mg in the afternoon or early evening) and don't experience sleepiness. I took Fluoxetine and the past and DID feel sleepy a lot.

The medication is basically speed this is an unusual side effect.