The Effect of Long-term Phenobarbital Administration on the Bone Mineral Density of Children

ABSTRACT

The long term administration of anti-convulsants on children with convulsive disorders may cause osteomalacia, depending on the dosage, duration, type and combination of anti-convulsants administred. Fifteen children, comprising 10 male and 5 female, dignosed with convulsive disorders and administered with phenobarbital for a long term period of more than 9 months but less than 84 months and 15 healthy children of a similar age-group were selected for the investigation the density of she spinal backbone of each individual was measured by means of the "QDR-2000 X-ray bone densitometer's (made by Hologic company) which uses the double energy X-ray absorption technique. The levels of serum calcium, phosphrus and alkaline phosphatase for each child were also measured for comparative analysis. The results were as follows 1) The mean bone density for the healthy group of chlidren was 0.69+/-0.09g/cm(2) and that for the group of children administered with phenobarbital was 0.59+/-0.07cm(2) indicating a significant decrease in density for the latter group (p<0.05). 2) As for the relationship between the duration of phenonbarbital and the decrease in bone mineral density, 5 of 6 patients(83%) administered with phenobarbital for more than 4 years showed a decrease in bone mineral density and 5 of 9 patients (56%) administered with phenobarbital for less than 4 years showed a decrease in bone mineral density. 3) the mean vitamin D level for the healthy group of chlidren was 26.8+/-2.5pg/ml indicating a significant decrease in vitamin D3 level for this group(p<0.05). 4) The mean serum alkaline phospatase evel for the health group of children was 240+/-50u/L and 462+/-110u/L for those administered with phenobarbital. This indicate a significant increase in ALP for phenobarbital group(p<0.05). 5) The posphorus and calcium levels were within the normal range for all the groups of children.