I wanna ask you guys some questions about your anecdotal experience with booster doses. How you've felt and what you've noticed is really important, tell me whatever you notice of the below:

I take 40mg of Vyvanse at 7am. I've been on this for 3 months now.

This dose only lasts me 5-7 hours, and before anyone says I should increase the dose, I can't because any higher dose affects my ability to articulate my speech and tell jokes. I lose what I'm trying to say or can't find it exactly 3-4 times a conversation and people notice, and it's really humiliating and frustrating (and also I've tried and even 70mg only adds about 1.5 hours to that chaos)

My doctor prescribed a booster of Vyvanse 20mg 4 hours after my 40mg. That's WAYYY too much and I get all the symptoms described, so I volumetric dose by dissolving the dose in water and splitting the water into two plastic water bottles to take 10mg instead. That works okay, I get a little bit of that during the first hour but then it mostly works as a prolonger for 2-3 hours more.

Here's the reason why I wanna ask you guys some questions. Steady state for dextroamphetamine takes about 5-6 days to achieve. You may recognize this feeling as "When I take a break, it takes 2-3 days for my dose to go back to it's peak effectiveness".

I wrote a script in PowerShell since I'm in IT to calculate steady state at 10 days properly (20 half lives) for Vyvanse once daily and for once daily with a booster 4 hours later:

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40mg once daily after 10 days

13.333mg lowest blood concentration (right before morning dose)

53.333mg highest blood concentration (right after morning dose)

40mg in the morning and 20mg 4 hours later after 10 days

21.73mg lowest blood concentration (right before morning dose)

61.73mg post morning dose blood concentration

68.997mg! highest blood concentration (after booster dose t 4h. That's 70mg!!)

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As you can see, if you take 40mg once daily, the affect you feel is actually what you WOULD feel taking 50mg for the first time, because after a few days your morning dose goes up to 53mg. This means that your booster doses aren't free, assuming that the body doesn't become tolerant to the subjective affects to ANY value left in your blood at the 24 hour mark making the previous dose irrelevant (but anecdotal evidence suggests that the body only becomes tolerant to some of this, and some high amount of your cumulative dose appears important.) Adding a 20mg booster brings your lowest blood level to 21 from 13 and the peak all the way up to a whopping 68mg! If 70mg is too high for you, then within a few days of taking your booster dose it's going to get real brain foggy real quick, and many of you might have already noticed this.

NOTE: These figures have a margin for error; drink with salt. Because Vyvanse's prodrug, lisdexamphetamine, takes anywhere from 0.7-1.5 hours for it's half life, so there's an additional calculation I did not run where there's approx ~1 hour lag time before the 12 hour dextroamphetamine half life should be run, and it would only be calculated at 50% of the dose, then 75% of the dose, then 87.5% of the dose etc etc, but this is a simplification for illustrative purposes and is still, indeed, pharmacokinetically relevant.

My question is three things.

1. Has a booster dose in the afternoon changed the effectiveness of your morning dose? I've heard that going up a dose and then going back down makes the original dose less effective, so why wouldn't that apply to here? It's an increase in the total mg your body is exposed to.

2. Has anyone noticed that adding a booster dose increased the rate at which you develop a tolerance to your existing dose, so instead of having to increase your dose every year or two, you have to increase it like every 6 months or 1 year?

3. Have you noticed needing to adjust your morning dose lower than it currently is after adding a booster so that you don't get brain fog/confusion/side effects? Or have you noticed the booster dose has little bearing on your morning dose's mg?

I want to hear your guy's experience and how it's felt for you. Also feel free to point out any errors in my assumptions/perceptions. I wanna start a discussion that might help a lot of people.

I've also tried making the post readable via skimming using bold and only highlighting the absolute need to know info if you get overwhelmed. I don't want to exclude anyone from the discussion. I put a lot of effort into making this really concise and then readable on top of that too, so I hope you guys appreciate it.

Thanks!

(My post was removed from r/ADHD for seemingly no reason, and I put way too much effort into this post for nobody to have the chance to think about it and discuss. I think discussing this would be really useful for people and refuse to let it just die.)

TL;DR: Adding a booster dose can significantly increase the peak of the drug in your system, giving you a higher dose than you expected. 40mg 20mg booster might make your morning dose feel like taking 60mg and your afternoon like taking a morning 70mg. In your anecdotal experience, have you noticed 1. your booster dose affecting your morning dose, 2. your booster dose increase how fast you develop a tolerance, 3. have you noticed needing to adjust your morning dose downwards to account for adding the booster dose because you were experiencing side effects/brain fog. Please let me know.