5-hydroxytryptophan and pyridoxine. Their effects in young children with Down's syndrome

Am J Dis Child. 1980 Sep;134(9):838-44. doi: 10.1001/archpedi.1980.02130210022007.


In a double-blind study, 89 children with Down's syndrome were given 5-hydroxytryptophan or pyridoxine hydrochloride in the first three years of life. The analysis of 5-hydroxyindole blood levels revealed that 5-hydroxytryptophan, pyridoxine, and the combination of 5-hydroxytryptophan and pyridoxine raised blood levels of 5-hydroxyindole equally well in 40% of the children. The assessment of muscle-tone ratings showed no significant difference among the study groups once children with moderate and severe congenital heart disease were excluded. Detailed studies of cognitive-adaptive function of children in the various groups found a significant difference ont the Vineland Social Maturity Scale at ages 6, 12, 18, and 36 months; yet the source of significance was a negative interaction affecting children whose parents were able to comply with furnished guidance; these children showed consistently higher levels of accomplishment.

Publication types

  • Clinical Trial
  • Controlled Clinical Trial
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Child, Preschool
  • Clinical Trials as Topic
  • Double-Blind Method
  • Down Syndrome / drug therapy*
  • Drug Therapy, Combination
  • Female
  • Humans
  • Indoles / blood
  • Infant
  • Infant, Newborn
  • Intelligence / drug effects
  • Intelligence Tests
  • Language Development
  • Male
  • Motor Activity / drug effects
  • Muscle Tonus / drug effects
  • Psychological Tests
  • Pyridoxine / administration & dosage
  • Pyridoxine / blood
  • Pyridoxine / pharmacology
  • Pyridoxine / therapeutic use*
  • Serotonin / administration & dosage
  • Serotonin / blood
  • Serotonin / pharmacology
  • Serotonin / therapeutic use*
  • Social Behavior


  • Indoles
  • 5-hydroxyindole
  • Serotonin
  • Pyridoxine