dexmethylphenidate
Meaning of dexmethylphenidate: Molecules come in left and right handed forms, and here only the working half is supplied, which is why the milligram numbers look smaller.
Definition of dexmethylphenidate
Dexmethylphenidate is a stimulant containing only the more active of the two mirror image forms that make up methylphenidate. It raises the amount of dopamine and norepinephrine available between nerve cells by blocking their reabsorption, which sharpens attention and reduces impulsiveness. It is prescribed mainly for attention deficit hyperactivity disorder and comes in short and long acting forms.
What does supplying one mirror image change?
Many molecules exist in two versions that are mirror images of each other, like a pair of gloves. They contain the same atoms in the same order but cannot be laid on top of one another, and the receptors they act on are shaped to fit one and not the other. Ordinary methylphenidate is an even mixture of both, and nearly all of the effect on attention comes from just one of them. Dexmethylphenidate is that half on its own. The practical consequence is arithmetic rather than pharmacology: roughly half the milligram amount produces a comparable effect, so a number carried across from one prescription to the other without conversion would double or halve the dose.
| Methylphenidate | Dexmethylphenidate | |
|---|---|---|
| Contents | Both mirror image forms | Only the more active form |
| Milligram amount for a similar effect | Higher | About half |
| Available as | Tablets, capsules, liquid, patch | Short and long acting tablets and capsules |
What is it prescribed for?
Almost always attention deficit hyperactivity disorder, in children and in adults. That condition combines inattention, impulsiveness and in many people physical hyperactivity, in a pattern present across settings and interfering with school, work or relationships rather than confined to one difficult situation. Stimulants act quickly, within an hour or so of a dose, and their effect ends as the drug clears, which is why the long acting forms exist. Beyond that, stimulants of this family have been studied for fatigue and for the slowed thinking and sleepiness that can follow cancer treatment, though the evidence there is mixed and such use remains secondary.
What comes with it?
Reduced appetite is the most consistent finding, along with difficulty falling asleep when a dose lands late in the day, headache, stomach ache and a modest rise in heart rate and blood pressure. Some people notice irritability or low mood as a dose wears off. Growth is followed in children taking it over long periods. Because the drug is a stimulant with potential for misuse and dependence, it is a controlled substance and prescribing is regulated accordingly. Each of these is a recognized side effect rather than a certainty, and their pattern is a large part of why one member of this drug family is chosen over another.
Used in a sentence
Dexmethylphenidate was prescribed to help manage the child's attention deficit hyperactivity disorder symptoms.
Good to know
Dexmethylphenidate and methylphenidate produce a similar overall stimulant effect, but dexmethylphenidate supplies only the more active half of the molecule, which is why it is typically prescribed at a lower milligram amount.