Drug Mechanisms and Side Effects

[TheSeanieB]

Can an ADHD pt take Adderall in the morning and Ritalin in the afternoon? Given the mechanisms and half lives (10 hours for Adderall, 4 hours for Ritalin), I would think that this would be an optimal treatment, especially compared to taking Adderall all day.

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[Merovinge]

The half-life of methylphenidate and dextroamphetamine salts very widely based on their formulations (they are not simply the numbers you posted). There are short, medium, and now long acting formulations for both, although the technology behind concerta (triple release methlyphenidate, very nifty) has not been brought over to dextroamphetamine yet as best I know.

One of the keys of ADHD is coming up with a regimen that fits that pt's life. Many do well on once daily dosing in the AM after breakfast, others have issues with appetite suppression and may need to stagger shorter acting formulations allowing time to eat in between.

Most research focuses with one of the two stimulants and not combining the two, which to the best of my knowledge has not been shown to be beneficial. Generally if a patient responds well to one or the other, there is a way to appropriately dose it to provide coverage for what they need.

Hope that helps answer your question.

 

[billypilgrim37]

Pet peeve: an extended release formulation of a medication does not change it's half-life. Half-life is a function of metabolism. Extended release formulations are based on altering rates of absorption. This doesn't have anything to do with your basic point, but I am always confused as to why so many physicians make this mistake.

 

[Merovinge]

Sorry, you are absolutely correct, it changes the average drug level over time and that's the clinically relevant part, but it was very bad wording and factually incorrect.

 

[heyjack70]

Pet peeve: an extended release formulation of a medication does not change it's half-life. Half-life is a function of metabolism. Extended release formulations are based on altering rates of absorption. This doesn't have anything to do with your basic point, but I am always confused as to why so many physicians make this mistake.

Agreed. Immediate release Adderall doesn't last 10 hours.

 

[SuperSoccer19]

I have mixed a short acting with a longer acting. For instance, I have used Adderall XR in the am and then a shorter acting adderall in the afternoon. I have done the same with Concerta/methylphenadate. I have never combined different preparations, but mostly because the situation will be that a patient has been on a longer acting and then will say, "It works great, but come 2-3pm I can feel it wearing off and...." so I already know they are tolerating that compound.

Honestly hate prescribing stimulants...but ill spare the rant.

 

[markglt]

i had a px come in to the er on that..aderrall in the am ritalin at lunch, and 150mg of wellbutrin xl bid...and recently put on latuda for bipolar, x 4, unreal,