One year treatment with clonidine in children with constitutional growth delay.

The therapeutic potential of clonidine was evaluated in 112 prepubertal children with short stature, delayed bone age and a growth velocity of 4.1 +/- 0.4 cm/yr in boys and 4.2 +/- 0.5 cm/yr in girls. The alpha 2 agonist was orally administered at 0.075 mg/m2 to 51 boys and 39 girls over a period of at least one year, and the effect compared to a vitamin treatment given to 10 age matched boys and 12 age matched females showing similar growth velocities. After one year of treatment growth velocity was increased to 6.6 +/- 1.2 cm/yr in boys and 6.50 +/- 1.0 cm/yr in girls treated with the drug, whereas in those given vitamins only 4.9 +/- 0.7 cm/yr in boys and 5 +/- 0.6 cm/yr in girls was recorded. Bone age remained 1.5 +/- 0.3 yr behind chronological age in both vitamin and clonidine treated groups. If only the 65% of patients that show a growth velocity increment of more than 2 cm/yr are considered the growth velocity reaches 7.20 +/- 0.82 cm/yr in boys and 6.68 +/- 0.75 cm/yr in girls, indicating that clonidine may be a useful pharmacological agent in the treatment of some patients with constitutional growth delay. The remaining 35% patients do not show any significant increase in growth velocity.