For individuals diagnosed with ADHD, you may be curious about the differences with currently approved ADHD medications. Here are a few helpful notes on ADHD treatment.

Stimulants are first-line treatment for uncomplicated ADHD.

Compared to non-stimulant treatments such as atomoxetine, guanfacine, or clonidine, stimulants have approximately twice the effect size compared to that of non-stimulant medications.

However, stimulants may not be appropriate for certain individuals who have negative reactions to them and have additional psychiatric co-morbidities such as psychosis or mania. This is when non-stimulant options are more likely considered.

What’s the difference with all these stimulants?

All currently available stimulants are based on combinations of the following:

1. Amphetamine vs methylphenidate-based medications

2. Short-acting vs. long-acting formulations

3. Isomer ratio (dextro- and levo-amphetamine / dextro- and levo-methylphenidate)

From a pharmacologic standpoint, amphetamine products theoretically can result in a higher release of dopamine in the brain. This may have clinical implications of individuals reporting a slightly higher effect when trialed on amphetamine-based products but also more side effects and abuse potential. Methylphenidate functions in a more indirect fashion to lead to more dopamine release in the brain.

Short- vs. long-acting formulations are fairly intuitive in their rationales. Some patients prefer the control of using short-acting medications once vs. twice a day; however, some patients find it more convenient to take a one-time medication once a day that lasts loner.

Isomer ratios are more complicated topics to explain. In short, both amphetamine and methylphenidate come in a mix of left (levo) and right (dextro) ratios depending on the medication.

Adderall, the most common amphetamine-based ADHD medication, comes with a ratio of 3:1 dextroamphetamine to levoamphetamine. As pharmacists developed different forms of amphetamine medications, they discovered that the dextroamphetamine version was more powerful than the levoamphetamine version. Subsequent drug makers have experimented with differing ratios of dextro- and levo-amphetamine resulting in individuals reporting different benefits and side effects depending on these ratios.

For methylphenidate, the dexmethylphenidate version is entirely responsible for the stimulating effect compared to the levomethylphenidate version. However, to make things even more complicated, sometimes combining these two formulations result in a slight lowering of peak effect, smoothing out the dose response.

The right medication from an individual with ADHD will often involve a careful assessment of the benefits and risks of that the medication provides.

For more information on left- and right-handedness in chemistry, you can read up more on chirality as a concept!