Can stimulants permanently stunt growth in children?

I have not seen previous reports of permanent growth suppression from long-term use of stimulants during childhood.  Expert consensus and my clinical experience is that height may be slightly delayed but is genetically determined (assuming adequate nutrition).

The package insert for methylphenidate products (Ritalin, Concerta, Focalin, Daytrana, Metadate), cautions that daily use in a controlled study versus a controlled group did show on average 2cm less height after 3 years – but it is assumed to eventually catch up.

Kids who don’t take medication on weekends or during summer don’t show this delay.  The presumed mechanism of the delay is that norepinephrine (increased by methylphenidate) leads to a decreased release of growth hormone during deep sleep, (normally in the first 3 hours).  This suppression of growth hormone can probably be prevented by use of Clonidine or possibly Guanfacine  taken at bedtime.

In the reader’s comment amphetamines were referenced but the statement was also made that the person referred to was treated with methylphenidate.  Of course both are stimulants but are significantly different.

The package insert on amphetamines (including Adderall and Vyvanse) cautions about below average weight gain over a one year period of daily use.  In the Vyvanse study the evidence was that at the beginning of the study the average child was at the 62nd percentile of body weight – since food is a natural booster of dopamine in the nucleus accumbens, patients on amphetamines are less likely to eat out of boredom and they usually lose weight.

In fairness, we do have more studies using methylphenidate in kids than amphetamines.  The longest controlled study ever, the MTA study was also predominantly methylphenidate.  Intuitively it would make sense that amphetamines would raise norepinephrine levels even more since they increase release in addition to blocking reuptake.  Empirically however, methylphenidate is associated with increased excretion of norepinephrine and amphetamines are associated with a decrease.  Presumably amphetamines are more likely to down regulate, ie, modulate norepinephrine levels.

The hardcore science for all of this is in its infancy.  We will undoubtedly find that there are “outliers”, but at this time with all the evidence I know of the long-term benefits outweigh potential risks for the spectrum of Attention Deficit Hyperactivity Disorder.

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